Originally Posted by L473ncy
I believe the downgrade you should be looking at is either an M100 or M110 spring (depending on other factors too).
I'd say if you plan on playing indoors a lot, even an M90 spring may be in order. M110 will more than likely hit 360+ fps which is no good for indoors... M100 will be about 340 - 350, but if a tightbore ever gets added, that will shoot up into the 360-ish range, also making it too hot. M90 + tightbore should put that gun in the 350 range.