I would also like to add that I have heard that the s15 tranny is also weaker then teh s14 tranny. So if you are looking for some serious power you may want to look at the s14. This is what I have heard. Since you guys are out in cali. you may want to talk to Non Fujita he owns this car
with this motor a s14
from what I have heard this s14 motor is fully build by Tomei he is beating vipers and daily driven. You don't have to go all out like him but I am sure he could give you some good ideas of what you may want to do. Here is his web site
Enonvativ Force