The majority of the TM8 issues can be boiled down to a handful of issues. The first and most common of which is with the charge box coming off of the throttle bodies. This can be remedied a number of ways, we strap the charge tube around then under the charge box and finally to the sway bar tube. (right or wrong it seems to work). As for the blow off, I have 1600 miles on my TM8 and have employed pretty much every commercially available blow off, and found the Turbo smart to be the best and most reliable, so yes we tested it. The next most prevalent problem is with Y-pipe cracking (sometimes even pipes), it takes only the smallest of cracks to set things awry, sometimes barely detectable by looking and suddenly it wont take fuel any longer. You find yourself leaning your 12 psi # alot to effect proper runnability. Surprisingly a 3/4" long crack can equal as much as 8pts @ 12psi. The answer is to inspect the y frequently and carefully, if a crack is found, remove and weld. Next is exhaust cap off in deep snow, for guys still running the old exhast..... get the new silenced exhaust. The new outlet design simply cures any related issues, its amazing. The next most common issue is not related to BD failure but an Arctic Cat failure, and is a CCU failure. This problem manifests itself as a severe lean popping on boost (bad, very bad) due to a dramatic lack of fuel pressure (and if wired to same harness the lack of aux injector function), this is caused by the loss of power to above said components (can be diagnosed by testing voltage to oil/fuel pump). Obvious repair is to replace the CCU. Another problem however not very common is the presence of water in the boost transducer and associated damage caused by freezing said water, the typical symptoms are erroneous boost readings especially at idle, and obvious poor runnability. I found by orienting the transducer fitting down it lessons the potential for stated damage.
Aside from that almost all other problems are generally caused by improper installation.
