how does your first gear pull?
 

I have a stock NA 1987 manual supra. In first gear when i really give it gas when i drive it to have fun and i bring it to 6k rpm's, i feel lots of pull until i get to about 4.5-5k then the pull doesn't seem so great. I thought we got most of our HP around 4800rpm's tho.

Clutch Slipping?

This is what you call your power curve. Your power will always peak then die off. That is kind of normal with a n/a really mine did the same thing. Now with a turbo you will feel the lag in the beginning and then it will also peter out on the top end unless you put a boost controller on it to take care of that.

i'm turbo'd and its like it doesnt even exist :P