I'll give you a hand here Kev
Jap80x - just keep in mind when modding an FTO for power there is very little in the way of 'off the shelf' go fast bits... In fact after intakes & exhausts, thats it - its off to the engineering shop you go. With that in mind - you will NEVER make 250hp without sticking a turbo or blower on it.
Having said that - I'll see what I can do with you list here....
extractors - available through RPW
www.rpw.com.au. Approx $600. These units pump a 2.5 inch feed to your cat. Once these are installed you will only get the full potential if you relace the cat, resonator, muffler with high flow units & some nice mandrel bent 2.5" stainless pipe. Another $6-800.
Throttle body - Also available through RPW
www.rpw.com.au
Easiest way to do it? Take your own TB down to an engineering shop & have them bore it out, fit a larger brass butterfly & machine the inlet out.
$100 worth of machining
n/a custom plenum - No such thing off the shelf. Again down to the machine / performance shop & have it ported to your specs. Some of us here have had it done.
injectors - No point if you are staying NA. The stock fuel system only runs at 60% capacity during full throttle using 167cc injectors
forged pistons/rings or stronger pistons/rings. - No point if you are staying NA. We have guys here running 6-8 pound boost on turbo FTOs with no issues with the stock internal. If you were to upgrade them, it would be purley for longevity reasons. Not only that, no-one makes a forged piston for an FTO motor. Its just not available. You'd have to strip the motor down, pull out the stockie & take them to a performace shop & see what forgies they could match up or modify to fit.
fuel system - Only item that we recommend upgrading in the fuel system is adding a 1.7:1 rising rate fuel pressure regulator. If you really need more out of the pump, there is an uprated aftermarket unit available from the UK
www.camskill.co.uk. There is also a minor mod you can do to the connector line that joins the fuel rails. Its a 1/4" pipe that chokes the rear bank a little bit a bit & as a result the front cylinders tend to run rich on FTO's. That pipe can be upgraded with some custom setup. The fuel rail can also be replaced with custom rails cut to size. RPW again can supply these.
racing leads and plugs - Leads are available from Magnecor
http://www.magnecor.com.au/ get some nice 8mm lead. You cannot go any bigger as the lead cannot be pushed into the Mitsubishi plug boot if its over 8mm
Plugs - I recommend an NGK Iridium unit. Other folks have different brand preference but tend to go for the same type of long life unit. Any auotshop can get these in for you
custom manifold - Not available off the shelf. Again, down to the machine shop & tell them to do what you want. Also something that some of us have had done.
cams - No hot cams are available for the FTO. You can buy a billet set from RPW for $2200, but you then have to specify the grind you want on them.
aftermarket computer - A number of options available. I dont recomment a complete engine management system. It simply doesnt need it, also the car becomes very rough when the stock ECU is removed... it runs more than just the air / fuel ratio. We recommend piggy back units when staying NA. Greddy, Apexi, Uniship, Perfect Power all make suitable units. All available through respective resellers & dealers. Price ranging from about $800 to $2000 installed & dyno tuned.
and so on...
As the Integra was released to a worldwide market - the world has had time & resources available to develope go-fast bits, especially in the states. The FTO was only ever intended for the Japanese domestic market. Eventually it found its way out to places like New Zealand & the UK, but with such small numbers that performance developement for them was not economically viable. We have to make it up as we go!
If you want me to elaborate on any of the above, just ask
I knew someone going to translate my chingrish sooner or later hahah