I have a Thermal exhaust and I love it. It has a nice deep tone and sounds great with my focus sport shorty header, random tech cat, focus sport flex combo. I've also heard the MBRP exhaust and it sounds good too. The MBRP exhaust is $319 at McNews
I think you will be happy with either of them
the mbrp can be had from www.mcnewsautomotive.com for $319 + s/h. the two systems are both very well made. stainless steel, 2 1/4" pipe, mandrel bends. the thermal is much more subtle as far as appearence and sound. it has a 3" tip that looks almost stock when mounted on the car and the tone is much quieter than the mbrp. the thermal also is only two pieces, eliminating the need for the central slip joint (a source of many leaks) and making the system a little more solid.
the mbrp is definitely louder and a lot more aggressive sounding. the 3 1/2" tip is a little more noticable (yeah i know, it's only 1/2" but it makes a big difference.) i have the mbrp and i like it. if i had it to do all over again it'd be a tough choice between these two and possibly the FS quiet system.