Hi all. I have been searching for info on the Thunderheader X-Series 2in1 for the M8 since I bought my 2017 RGS last year and found mostly nothing. I finally said screw it and pulled the trigger and ordered a set mostly sight unseen. Because I couldn't find much I figured others may be looking as well so decided to post some pictures here.

 

Nasty as man.

 

 

Psycho dad , Psycho dad ! (Al Bundy)
Cool stuff boys.

 

People can bitch about Thunderheader's customer service (it sucks), chrome quality (awful or at least used to be), sound, dyno performance (kick-*** if you're not afraid to do a little bending on the baffle vanes), etc., etc., blah, blah.... But at the end of the day there's nothing like a Thunderheader to make the hair on the back of your neck stand up. Period.

 

 

 

It sounds great but why do they make the muffler portion look so weird, that part alone is a deal breaker for me. No disrespect to the OP or anyone else who has this, I know looks and sound are both subjective.

 

Thats just part of the design, and what makes them work. Thunder Header has always been among the top performing pipes for a long time.

 

I wouldn’t get hung up on any particular 2-1 as most of them are very good on the power.
So close you wouldn’t feel the difference by the seat of your pants. I would go with what looks is best to you. What price you feel comfortable paying and what sound you like the best but I am not sure I would read to much into what you hear on a u tube clip. When I recorded my bike so people could hear what it sounds like, it didn’t sound anything like the real deal.