I have been looking around, but with my supporting mods what pulley size can I drop to? My 2000 Ssei has about 60k miles and in great shape. I am thinking a 3.5 and will get a tune.looking to spend around 300 or so

You should be able to safely run a 3 1/2 with those supporting mods. I would get something that reads KR; just to be safe...

A 3.5 should be safe, but you really should scan for KR. The 2000 plus tend to run more lean and can see KR sooner. The headers are nice, but don't help a whole lot unless you put rockers or a cam in. The engine will only breath as good as the most restricted spot, and that'* your valves. Don't look as much at pulley size. You want to run the most timing you can with the smallest pulley. No less then 15*, but really no more then 20* or so. And that'* where a good tune comes in.

well in the last few day i added all of the previous mods, dropped down to a 3.4 pulley, ported heads and put on some roller rockers. i still have the stock exhaust but have a 3" downpipe and high flow cat. Scanned for kr and got 1-2 the first time i scanned. then nothing the second and third. Everything on the car is running great and looking for some more power. Got enough money lieng around, what is involved to twin charge it?

Headers or a Plog should be your next step.

As for twin charging, are you talking about a turbo and a supercharger? There was a guy here that did that. And if I remember right, he chipped a lot of pistons.