While we're on the subject of SVIs... so what's the deal with those? If you want an MA compliant one, I'm guessing you have to buy it the way it's configured.... or is it one of these deals where you buy a "base" gun thats compliant and have to send it back to the factory to have (whatever other options) you want put on it?
Neither, really.
Either can be had in any caliber from .45 ACP on down to 9mm (which is to say, pretty much any autoloader caliber you'd want); with any trigger group configuration you select (no "Mass. trigger") and any target (read: micro-click adjustable) sights offered. Magwells may also be added.
If the bloody "target pistol" law ever gets competently drafted and implemented, you'll have even more variations to choose from.