mine will be 150 there abouts. Let me know if you come across any used ATR downpipes. I have been looking for a used ATR, but had no luck. There are some hot air downpipes that work only in conjuction with that brand header. I believe the kenne bell headers are like this. You will need that whole system to make it all work, so be certain of the what is for sale. The ATR will bolt right in more or less, you may need a few curse words to get it in. Other than ATR, i think Lee Thompson and maybe Terry Houston make a 3" version - someone correct me if am wrong. And accordingly are more expensive. "Zero to Sixty" used make a handful of 3" dp, so every once in a while you see those pop up for sale. The downside of 3" is clearence. They make it difficult for spark removal and associated activities, however they also come as a two piece design, which will eliminate some of that trouble. There aren't really to many options out there, unfortunately. From what i understand from others here on the board, Lee Thompson, ATR, and Terry Houston all make excellent pieces - again someone chime in they feel differently. I think Keith Mease makes them as well. I would just watch out for some homemade pieces, some are well built and others aren't.
( i am not sure if Terry Houston makes or made one for the hotair.)
Nathyn