After Market Radio Harness AMP bypass

[Elvis]

I am a proud owner of a 92 MKIII. While the car does need a little love, I thought I would start with a aftermarket stereo. I have installed more car stereos then your average person. I have always hated the idea of cutting the factory wiring. I am a big fan of the aftermarket harness. There are connections on the radio that I have never seen before. The factory radio has 2 antenna leads. One is the standard one that fits nearly all non-GM cars. And the other is a much smaller one. But the issue at hand is the wiring harness i got from CarToys is not fitting the factory one. Is it possible that the under seat amp has the correct leads for the aftermarket harness? Has anyone been able to bypass the amp and use this aftermarket harness?