I had a 1g short route kit on my car, with the 1g j-pipe and it worked fine with the stock radiator with one caveat, and that was that I had to shift the radiator to the side (forget which, but search for one of my posts about radiators and there's a picture... I did it 13 years ago and can't remember off the top of my head). Piping fit fine, with a slim fan, though I still think it would be a problem with A/C...