I have an S15 T28...car feels good but I know with a tune it would feel better...I don't really go by numbers I go by how good the response is and drivabilty... Jaime has a T28 550cc and Power FC tuned and that car feels great... I remember when aaron still had an sr in his s13 that car felt scary...
You should chat more with jaime about the cost vs bang of his t28 setup. I think he would say just keep the t28 on a fairly stock setup with just a fmic, fuel pump, boost controller set at 10-12 psi ( 10 would be safer ), exhaust, and thats about it. Do an adjustable wastegate for even more durability and skip the boost controller. The next step is a fairly expensive one, going for the injectors, power fc, z32 maf/map sensor, tune, etc. that is easily a 2k dollar list no matter how you cut it! you can safely run a few lbs more on that setup with all those extra parts, but that is a lot of money for the rest of that hp. and your car has enough hp as it is now! i think when you jump up to the next level, 2871, that is when its time to go balls deep. the t28 just is such a nice well rounded setup with the stock ecu, its hard to give up that simplicity unless you really need more hp. stock ecu means you can diagnose ecu problems easier, parts are cheaper, you have more money to go drive and have fun, go es-swimming.
I know this thread is old and I don't really get on here much, but when I read Aaron's post, I thought I'd give my input to back up his reasoning. Reason is my power fc recently failed and I was forced to go back to stock engine management, injectors and maf. I now have great drivability, idle, and don't have to worry about getting the thing tuned anymore all after taking $2,000 worth of parts/effort off the car. As far as power goes, the car feels just as fast as when it was tuned. When I had my power fc, i remember I was able to trap 109mph @ about 1.1 bar. I took the car to the track now with stock management and was able to easily trap 105mph on just 12psi. I feel that if I turn up the boost to about 15psi or so I should be close to 109mph again in the 1/4. Pretty much the same power as with the tune except with much better drive-ability and cold idle. Plus no more infamous power fc idle surge!
Sure this car is not making crazy power, but Aaron also makes a great point that on a t28, it is not worth going to the next step of getting engine management, larger injectors etc., as you typically need to spend about 2k extra for not that much more power at all. The stock ecu handles t28s just fine. My car is on the s15 t28.