ok so i've been looking around for an aftermarket air intake to improve my car and so far all i have found is the blitz lm system on racingbeat.com if any one knows if that is a good one or knows of a good aftermarket air intake system for a 1991 convertible that would be great.

 

Search CAI, which stands for Cold air intake. Should be tons of results. There are lots of companies that offer stuff, but they're mostly just filters, not really the whole pipe.