Another voucher for Promotion Powertrain. They have built 2 T56s for me that have been great. They are also an awesome source of knowledge and support. I still go back to them whenever I want the ground truth on something I'm struggling to figure out. They're great people, too. Walt's helped me research and find parts for custom builds without even charging for it.
Now, regarding advice, I'd rather spend twice as much on a part I know will never have another problem than 1/2 as much on something that might break. A T-5 is kinda like that. I blew up a T5, probably because of a Spec Stage 3 ceramic clutch in a ~320rwhp H/C/I build on Nitto Drag radials. On the other hand, I've beaten the living hell out of the T5 in Black Jack, and I'd invite anyone to come drive it... it's still shifting perfectly. The differece? A/S tires, King Cobra organic clutch, & 270 rwhp are nowhere near as hard on the transmission as the other setup and maybe this Trans was built on a Tuesday.
So, my advice boils down to your budget and how you plan to build/drive your car. If you've got the spare change or you're going to put some big power down on sticky tires through an aggressive clutch, upgrade to TKX or T56 -- expensive but fun. If you don't or you won't, then keep your KC clutch and keep street tires with non-R compounds to reduce the torque/shock to the transmission.