I have the Bassani Road Rage on mine but it was not my original choice. I originally wanted to install one of Frank Drago's exhaust but apparently the large cam cover caused a fitment issue. The Bassani is much louder than I would have liked plus you can't check you oil level when it is hot since there is no room to get to the dipstick without getting burned. I tried to contact Steve @ GMR since he installs quite a few S&S 124 crate motors but he was in the process of moving so I was never able to get in touch. Since you have the winter I would do a lot of searching, you can check with Steve @ GMR, Frank @ Drago's, you can also contact S&S directly and ask who is doing a lot of 124 installs. Star racing also has some info. Steve @ Fullsak might have something that will work. At this point I'm not planning to replace the exhaust unless I locate one that is fairly quiet and still has decent numbers, I would trade some performance for a quieter system. What fits on a good performing HD 120" may not fit yours since the cam cover is smaller and gives you more choices. I believe there is a vendor on this site that was able to make one of Franks exhaust fit, maybe he will have some info for you. R&R motors builds a bunch of billet motors all the way up to 155" and their cam chest cover is similar in size & they use the Bassani. It may be a case of what fits and not what's best, I just don't have that answer. At least you have time to get what you want.