so i have an 88 vert n/a. whats my best, cheapest, easiest option if i want to make 350-400hp? s5 tii? ls1? etc etc

 

"Best, cheapest & easiest" are not really compatible descriptors, so pick one.
In fact, you can drop "best" altogether because one man's "best" is another's "blech".

How did you pick 350-400 as a target?
Once you get to that horsepower level, how much work are you willing to do to keep it?
What kind of driving are you doing?

 

Not even sure where to start on that one.....

I guess the first thing you want to do is ditch the NA.. Even if that sort of HP was possible in an NA, it would cost a fortune.

A TII with a hybrid turbo and a decent EMS would probably do. Don't forget all the small stuff too.. fuel system, exhaust, cooling, etc.. Still probably won't be very cheap though..

 

The "best bang for your buck" is probably going to be a TII swap. You'll want engine, trans, rear end, axles, 5 lug hubs (if you don't already have), ecu, etc.

An S4 TII swap would make it a little less complicated.