I'm very satisfied with the BTR rollbar. The removable sidebar enables normal access when not at the track, but is extremely easy to install once there. I had absolutely no issues with travel of the stock seat either before or after lowering it by 2 inches. Rear vision is not impaired whatsoever. At the local track, I refuse to race with a roof in place on my RT/10. On a typical grudge night, I'm usually the only street car they allow to run *******. The techs gave the BTR rollbar a very thorough examination, including the attachment methods, and were impressed with both the quality and design.
BTW, I'm 6'3".