Peter basically said it all. NOT POSSIBLE. Head has to come off. gotta pull the engine (mine's currently still in this state), I don't think it would even be possible to cut corners by leaving the block in the car.
Good luck, and be aware that when ordering new pistons/rings (bearings if required) there is info off the block/pistons & bearings you need..it sounds like you have possibly oversized cylinders?
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Temporarily Busted
93 Talon Tsi AWDREALLY pissed off at that freaking b.s. (aka bull sh!t) belt!
www.geocities.com/MotorCity/Street/1125/