Take an afternoon and have a read, there is LOTS of info around on turboing 4As and which responds best to what.
My opinion is that the blacktop is highly strung as is, turboing it will just be pushing it more (However Beau Yates drifted a turbo blacktop for a year or so).
Best start with a ZE for the lower compression. Or if you want 20V bling then drop ZE pistons into a silvertop.
However, as I said this has been worked over alot on here and elsewhere on the internet, so do some searching.