This has been a fun thread.
I just read through the many posts and have several comments:
Am I the only one that recognizes that dishes that deep ARE the valve pockets, and those pistons look like they could handle an .800 lift cam?!? Stop fretting over valve clearance. You've got plenty.
Milling heads: Great idea for raising the compression, however no one has told the OP that milling the heads enough for a compression boost also requires milling the intake. Info he needs to know.
Titanium retainers: It was mentioned that they are a small part, so the fact that they weigh half of hardened steel retainers means nothing. Yes, it does. In your hand, that weight difference feels tiny, but on the end of the valve at 6k rpm and the G-forces involved, it makes a huge difference on parts life and valve response.
X-pipe: You said one of the reasons you run cats is the car is too loud, well, an X-pipe is louder than an H-pipe. Maybe you should swap? H-pipes have a heavier 'bass' tone, while X-pipes rasp.
Also, across the power band, H-pipes are shown to make more power. As an average, X-pipes make less power, although 'Dr Gas' (forgot the man's real name) says he makes them for NASCAR and they find a 2% power increase in the narrow band those engines run, so X-pipe it is for them, but he said for drag racing or street performance, the H is always superior. So even if you run for hours at the RPM Dale Jarret does, you'll only gain 2%... What's that, 6 horsepower at 8500 rpm? Power loss everywhere else...
Just some thoughts.
My opinion, worth what you paid for it.
