I don't know too much about the RB, but I own 2 353's and ran them all last season. They are perfect for Floyd but if you want the fastest motor at Floyd that's not it. Those 353's are for the price, the best for the money. The TX looks nice and thought about it myself. I just got a Murman modified RB M3 for a good price and ran it this past Sunday, if the TX is anything like that, BUY IT!! My car was one of the fastest out there, it just lacked a little HP but I ran a brand new car and still have some work to do. Once I have the time ill go to Floyd and work on clutch setup and maybe gearing. But I'm only going to run Murnan motors from now on