I have one. The 12cm2 housing was done by TST Products in Columbus, Indiana. It's off the truck right now, but I had it on there a long time, and it didn't blow. The sound was awesome, the throttle response was eye-popping.
No regrets about trying it, though. I'll run it again in warm weather for some 1/4 mile times.
You'd be better off getting an Hx40 from Piers, he has a new Super Hx40 that is built to be more durable, and with near zero lag. Without the excessive pressure that is probably the main culprit for the blown units with 12cm2 housings.
Piers' Hx40 uses a 4" outlet, and has slight modifications to eliminate the lag. He doesn't use 12cm2 housings.
www.piersdiesel.com look him up, get one !
I'm running a TST PM3, Competition, with a modified fueling curve & duty cycle. Also DD3's. I had a Van Aaken on there too. And propane.
Afraid of breaking the transmission? LOL. Enterprise Engine is 4 hours away, no problem.