Mine have the DB killers and they get hot enough to melt stuff that's on them (my waterproofs that were strapped round the passenger bars got a hole in) but they're not too bad.
just put my Two-Brothers on and they are good looking, as well as add to performance. However, they are loud...even with dB killers. Wish i would have got a set of the older Scorpians with the turned down snorkel...I just like those. And they are quieter.