Some of this information may change as products are constantly being altered for manufacturing. If you find something on here in error, please do the community a favor and let us know so we can make a modification for the masses.
The information contained here is generated for the 9mm platforms mostly. We haven't had another caliber M&P since 2012 and typically don't get many requests for their modification.
Magwell / baseplate compatibility
M&P 2.0 Competitor magwell
+Springer Precision +4 / +0
+Taylor Freelance
-Does not fit Taran Tactical
Ed Brown low profile magwell
+Ed Brown baseplates
+Warne baseplates +3/4
+Taran Tactical +3/4
+Taylor Freelance Extended baseplate
- Does not fit Taran +5/6
Carver Open / Heavy magwell
+Arredondo (May require mod)
+Springer Precision +4 / +0
+Carver Customs 140mm/170mm
+Taran Tactical +3/4
+Warne +3/3
+Taylor Freelance - all styles
-Does not fit Ed Brown
-Does not fit Hyve
Floyd's Custom EDC magwell
+Floyd's baseplates
+Fits Ed Brown baseplates
+OEM Competitor baseplates
-Does not fit Warne +3/4
-Does not fit Taylor Freelance extended baseplate
-Does not fit Taran +3/4
Floyd's Competition magwell
+Floyd's baseplates (low pro baseplates not recommended)
+Taylor Freelance baseplates
-Does not fit Taran Tactical
Springer Precision Magwell
+Springer Precision baseplates
Taran Tactical Magwell
+Taran Tactical
SLR Magwell full size
+SLR baseplates
SLR Compact
+Claim usability with OEM compact mag black round/square hole baseplates
+SLR baseplates
+Floyd's baseplates
+Ed Brown baseplates
+Taylor Freelance baseplates
-Does not work with OEM square hole FDE plates
Tyrant CNC & Carver Tactical Magwells
+Work with all OEM and aftermarket baseplates
-These aren't real magwells due to the lip design internally
Ebay magwell
-Oem 23 round mags
-Taran Tactical baseplates
Iron Sights
-The size of iron sights differ from non-optic ready variants to factory optic ready variants. The dovetail size is different, and they will NOT fit in one another's slide.
M1.0 & M2.0 parts compatibility
-The trigger bar designs are different and not cross-compatible between 1.0 & 2.0
-1.0 & 2.0 sears and strikers are interchangeable, although both are manufactured with different angles and materials. This produces a different feel when used.
-Slides from the 1.0 will work on a 2.0 frame, but will NOT lock back. The 1.0 slide needs to be milled to function properly.
-Long slides from the 2.0 are wider than a 1.0 slide. Holster incompatibility should be considered.
-Striker channel liner is different between the two. White is for 1.0 and red liners are for 2.0 variants. Gray liners are for 45ACP/10mm. 45ACP/10mm liners are interchangeable between 1.0 and 2.0 variants.
-Strikers are interchangeable, but the 2.0 striker has a different angle for improved trigger feel. Interchangeable across all platforms and calibers, including the Shield EXCEPT 45ACP variants.
-Plunger can be used in all models of M&P pistols across 1.0 & 2.0, including the shield and all calibers. Shield 45ACP uses a different plunger.
-Trigger return springs are cross compatible between all models and calibers of 1.0 and 2.0 variants.
-Manual thumb safety levers are cross-compatible between all calibers and sized frames of 1.0 & 2.0 EXCEPT the 5.7 variant pistol.
-Grip frame plugs for the manual safety holes are compatible across all platforms of the 1.0 & 2.0 variants and calibers.
-Extractors are not cross-compatible between 1.0 & 2.0 variants. Each will fit all calibers and sizes of pistol EXCEPT for the Shield variations.
-Slide endcap plate is interchangeable between the 1.0 & 2.0 variants EXCEPT the 2.0 45ACP pistols. Shield endcap plates are different altogether.
-M2.0 full size and compact can interchange slide assemblies and frames. Compact slide requires a compact guide rod, full-size slide requires a full-size guide rod.
-M2.0 subcompact frame and slide are proprietary and not interchangeable with compact or full size frames or slides.
-Barrels are interchangeable between 1.0 & 2.0 slides for that caliber and length.
-Not all aftermarket 1.0 3.5in compact barrels work with 2.0 3.6in slides. OEM 1.0 3.5in barrels work in 2.0 3.6in slides. Neither work in a Shield slide.
-Extractor retaining pin can be interchangeable between the 1.0 & 2.0
-Extractors are NOT interchangeable between 1.0 & 2.0.
-1.0 & 2.0 takedown lever are not interchangeable.
-2.0 takedown levers are interchangeable across all calibers, including 45ACP and 10mm as well, EXCEPT the Shield.
-1.0 takedown levers can be used on full size and compact 9mm/40/.357 frames. Sub compact uses a different lever.
-2.0 takedown lever can be used on other 2.0 sizes and calibers like the above 1.0 information.
-1.0 & 2.0 locking blocks are not interchangeable
-1.0 9mm/40/.357 locking blocks fit full size and compact frames only. 45ACP and shield use different locking blocks.
-2.0 locking block fitment is the same as above.
Smith & Wesson M&P M1.0 & M2.0 9mm barrel & 40 slide conversion.
-In the rear portion of the slide, the notch at the back of the chamber hood is wider on the 40 slide, hence the external differences in the barrels. A 40 barrel will NOT go into battery in a 9mm slide, and a 9mm barrel will not lock up completely in a 40 slide.
-The feed lips are wider on a 40 magazine. If you shoot 9mm in a 40 mag, the rounds will sit too high in the magazine and should cause feeding issues. 40 rounds won't feed through 9 mags since the lips are too narrow (for the narrower 9mm case).
-To shoot 9mm SAFELY in a 40, you will need a conversion barrel (external dimensions of a 40 barrel, but with 9mm chamber and barrel), and 9mm magazines.
-Otherwise, the 9mm and 40 are identical, and share the same part numbers, including recoil springs, extractors, ejectors, sears, everything.
Backstraps
-1.0 & 2.0 backstraps are interchangeable, and all calibers
-The backstraps from the 1.0 compact do NOT fit the 2.0 compact or the 45ACP variant 1.0
Shield parts compatibility
-1.0 and 2.0 slides are interchangeable on each other's frames
-4in Shield slide can fit any Shield frame
-Shield plus frames can use Shield 1.0 & 2.0 slides. Shield plus magazines must be used.
-Shield 45ACP uses a different striker assembly.
-Striker channel liner is different
-Plunger is different in 45ACP models.
-Guide rod assembly is the same across 1.0 & 2.0 platforms for all calibers EXCEPT the 45ACP
-4in Shield uses a different guide rod assembly.
-Uses different takedown lever than other M&P variants. Can be used across all calibers of Shield pistols, including the 45ACP.
-1.0 & 2.0 takedown levers are interchangeable with each other. Calibers also except the 45ACP
Slide stops
-Different geometry between the 1.0 and 2.0 variants. 1.0 slide stops work with both slides, the 2.0 will not activate a slide lock-back.
-2.0 extended slide stops can't be purchased separately from S&W. Any that you find for sale online and marked "extended" are from pistols that were parted out.
-Compact slide stops are differently sized than full-size slides.
-There are several part numbers for these, some come with a spring and some do not. They can be used on one another.
Metal Frame
-A common complaint we hear about the metal frame is the rattle or loose front grip frame plastic insert. An easy fix for this is to remove the front plastic piece, apply a small strip of electrical tape on the underside of the insert, and reinstall to the frame.
-Most parts are interchangeable from the polymer 2.0 variants to the metal frame variations.
-Locking blocks from the polymer frame will fit inside of the M&P metal frame, but an additional polymer insert comes with the metal frames for locking blocks. This OEM part must be present for locking blocks to be swapped back and forth from other 2.0 pistols.
-Aftermarket trigger manufacturers will differentiate between polymer and metal frames when selling their trigger kits. This is due to the trigger overstop travel plug that must be removed and replaced with a threaded plug typically.
-Slides, barrels, sear housings, sears, triggers, backstraps, backatrap frame tool, guide rods, frame pins, iron sights, magazines, & takedown levers from polymer 2.0 pistols will fit the metal frame.
-The magazine release is DIFFERENT on the metal frame, and will not be compatible with a polymer frame. It is an entirely different design.
-Magwell compatibility is hit or miss depending on manufacturer. Numerous companies make two different sized magwells - one for the metal frame and another for a polymer frame.
-The magwell from an OEM Competitor metal frame will fit 2.0 polymer frames.
-The Carver Open magwell / Heavy magwell fit the polymer and metal frame M&P's.