the Jim Wolf Site is
http://www.jimwolftechnology.com
I have the Ecu Upgrade on my car, and I think it works great. It ups timing, moves the rev limiter up a little bit, removes the governor, and so far hasn't caused me any harm.
As for an intake, I have a JWT Pop charger on my car as well, as far as performance goes it's kind of a toss up. But I like it, becuase after 5,000 Rpm, your J will make a real mean growl. Again, I haven't had any engine problems with this on.
You can also get Unorthodox underdrive pulleys (
http://www.stillen.com) for you car too. They help a little, but if you plan on putting a large stereo in your car I don't recommend this, the stress on your alternator will kill it.
Stillen headers can be installed but they are a pain in the *** because they don't fit perfectly. Other exhaust work can only be done customly, but the J has dual exhaust and major gains are going to be hard.
I was going to buy a ALC from HKS (
http://www.hksusa.com) which monitors line pressure in your trans. I heard it's supposed to help out automatic trannys, but I never considered it. I'm getting a manual conversion this month...
Performance mods are hard to get, the J30s VG30DE is pretty maxed from the factory. Don't expect any cheap mods for big horsepower.
Oh, and this doesn't help much for performance, but stillen (
http://www.stillen.com) makes a polished upper plentum that looks really cool. A guy named Willis on this site has that along with a custom dual-exhaust. check it out on car domain.
http://www.cardomain.com/memberpage/358033
Hope this helps, welcome aboard!