Brock don't make exhausts, they are made by exhaust manufacturers to his specs. They make good power because he takes the time to do the research required to find out what works best. I've never bought anything from him, (overpriced in my opinion) but he has a reputation for excellent customer service.
I shopped 4 years ago. I was looking for power, price, and quality. My 4-2-1 stainless header makes around 15 RWHP, was decent quality, cost around $800 at that time and came with a MAP. I've seen slip-on's hundreds of dollars higher than that. I had it installed as part of the purchase because I'm too darn practical. I think my exhaust system weighs around 8 pounds. For a lot more coin I can get a Ti system that weighs a few pounds less, but skipping a meal does about the same. I wished everyone would do the research because I found some amazing data during my search. There's people out there paying a lot of money for systems that don't produce results. I've also heard stories of folks that have great difficulty changing oil filters and melting plastics. Can't say if that's quality of install or design / manufacturing.
I was thinking he had some of the cheapest pipes out there, but I might be wrong