I ran my Road Rebel in sr rotax for a year and I liked it a lot. Being a 32mm it’s was noticably stiffer than the Blackstar and KT1 chassis, but it worked well with the mojo tires and the needs of the rotax motor. It was definitely different in the way we tuned the chassis compared to others on the softer stuff, but never had an issue of the chassis being off pace, only the driver(me). Also it lasts much longer than all the soft chassis and was a little more consistent.
The only big factor is what track your going to be running at. My home track NJMP usually has a lot of grip so the thicker frame made it easier to not get bound up and start handling weird. It was also fine at englishtown, which is a low grip track, we just had to dial in more grip for that track. If you think you will always need to find grip, go with a softer frame that’s much easier to work with having grip right out the box and be super flexible.
The last thing is which Class will you be racing in? If its seniors or masters its probably an ok chassis, especially masters with all that weight. If juniors, forget about it as its just to hard a frame.
Sorry this post is so long, but figured I would put In my input having used the chassis in senior max on the east coast.