OK, here's what I am going to do/have done with my engine;
1. Upped exhaust to 3inch. It's excessive, but I plan on getting a 1JZ soon. 2.5" is plenty enough. By the way, when people say they've added a bigger exhaust it usually means they've also matched their downpipe and turbo elbow with the same size. Just doing the exhaust piping is not enough.
2. Get a CAI (Cold Air Intake) and a "more-flow" type AFM. There are several types of upgradeable AFM's to choose from, including the famous Lexus AFM. I'm going to be using this one;
http://www.horsepowerfreaks.com/sale...rchkeyword/AFM
3. 550cc injectors to go with the newly upgraded air intake system. More air flow = more fuel needed else lean out condition will occur.
4. Also need a fuel computer to tune it all in now that you've completely circumvated all your stock ECU running specs. Some choices are Apexi S-AFC, HKS VPC (which are discontinued now, but still work great), or a Blitz unit though they're harder to find.
5. A wideband type O2 sensor. MUST HAVE for accurate tuning.
6. Exhaust headers. You NEED this before getting a boost controller. I'm buying this one from OBX since they are the only manufacturer I can find that does one for the 1G-GTE twin turbo design. If you're going to switch to a single turbo, then good luck in finding a header.
7. Boost controller. Lots of good one's out there, just be sure to get a electronic unit if you can afford it. The mechanical one's, though getting better, are still prone to inaccuracies.
8. Either replace the 2 stock CT-12's with larger twins (still can't find any direct bolt on's) or get them rebuilt to larger trim sizes. Nice thing about the twins is they spool up faster than a single does, though sometimes that's not to be desired...
9. Aftermarket intercooler. Any one that you prefer that will fit will be better than the stock one. Not to say it's horrible, but after all these other upgrades, it will NOT give you sufficient cooling. I believe the stock piping is of an acceptable size, though you may wish to upgrade to metal/carbon fiber piping for safety reasons.
This is pretty much all the major stuff that needs to happen in order to make any sort of decent power gains. I'm assuming you're already thought of upgrading the brakes, bigger clutch pack, and removing dead weight from this tank of a vehicle? I thought so...
Anyways, there it is. Good luck and post pics of your 1G; I haven't seen any others either!