if you want to power 2 amp you should go 4gauge, or simply past a second 8gauge when you will get the second amp...

but i think getting the 4g now will end up being easier and less trouble

1998.5 Toreador Red/Midnight Blue Contour SVT - #5912/6535 - DOB - 05/11/1998 - RU-3530/CTA Intake Pipe MSDS Heaser/Y-Pipe Magnaflow #10435 9mm Ford racing SPEC Stage one/Spec Alum. Flywheel HERE