what would be the best aftermarket base intake for the stock plenum and runners.......as well if they were possibly ported? it's a 91 tpi trans am by the way not that it matters much i guess.

 

Stock is the best one in terms of being the cheapest. It is already there. Unless you hog out the runners and plenum, it is kinda useless. I stuck stock gaskets on my Accel manifold and you could see the big difference. The gaskets were way the hell small