I was running a E-303 cam on my car when it was speed density and it seemed fine, although it did have a surge at idle of about 200 rpm not to big. some put a check valve in the map sensor and this seems to do the trick for a little bit. I went with mass air and it cost me a total of about $155.00 the new a9l comp from discount was 102.00 out the door including tax, and pro-m sells the adaptor that will alow you to still run your speed density harness with the mass air, and this costs $53.00. You could pick up a used stock mass air for pennys on the dollar. If this is something you are interested in call (24 541-4780 and ask to talk to FLETCH and he will help you, and if need be talk you through it. it took me about 30 min for the install hardest part is finiding the #60 pin. if you need help pm me.