Lol, what makes you think that??
I ran a stage 2 box with a genuine 250bhp 1.6cvh for a 3 years.....did manage to break the cwp on the first one but only after 2 years of abuse (track/pod and did brunters with it too), a £350 rebuild and all was good again till i broke the car the following year
I went through 3 or 4 other boxes prior to having the cts box and it was definately the best i'd had, though i did find at the time that they weren't great to deal with, namely waiting times way longer than quoted!
Tbh now the mtx is the way to go if you want a strong box and they're not overly expensive either just a bit of work to fit, if it had been a proven conversion back when i had mine i would have bit the bullet and got one fitted