Truckracer, I see no issue with steel bolts as long as engine temps are kept within reason. I baited Dirtybird to a certain degree when I asked him about engine temps. Most guys are not going to have a temp gun, I have been running gassers for 15 years and have not needed one often enough to justify the cost. If I'm having issues with muffler bolts coming loose I just take it as an indicator that my engine is getting too hot.