I have the TRC full system on mine. The sound is great. They both use the same header pipe the only difference is the cans. If you are talking about loosing weight, the stock header pipes weights 15lbs and the cans are around 14lbs each. You will tell a small increase with the slip-ons, but can tell a BIG difference with the full system. If you look on the Yosh website, they say there was an 8 hp gain with the TRC, no dyno sheet on the R77, but I would guess it to be round the same gain. And the full system weights about 10.5 lbs vs 44lbs. I paid $784.00 on morepoweracing.com for the TRC system and $274 for the PCIII. Both come with free shipping.