If you were going to go to the effort of tearing it down and building, I'd throw a cam and rockers in as well. For stockish compression ~9.0:1, I'd probably look at a Schrick 272. Should give you a few more HP up top without sacrificing your low end. If you got crazy and decided that you needed high comp pistons (I believe you can go as high as 10:1 and keep the valve reliefs, 11:1 is possible if you don't keep them) I'd shoot for a Schrick 282 or 288, or a Catcam (look at digger's build on E30tech, he built a 3.1L stroker M20). Although I will say this, if your engine is running just fine now, no problems (low compression, burning oil, etc) I would just continue to save your money until you can afford what you REALLY want. Me, I REALLY want a OBD-I S52, however, my M20 is sick and I don't think the motor will last long enough for me to save up the difference between an M50 and S52 + OBD-I swap. Although I'm still hoping in a 4-6 weeks when I'm ready to buy a motor, I'll find a good deal on an M52.