Well, we don't exactly know what set up Mercman has, Keisler, Classic 5, Darkhorse, etc,.....I'll speak from my experience with Keisler, after installing many of their several versions of TKO 5's, and AOD4, the only failure was one hyd. master cyl. and one input shaft, the input shaft failure was due to a rather inexperienced "employee" who had "forgotten" to install the front BEARING! when installing a Hyd clutch set up,.......other than that NO failures since 2002 on any Keisler equipped vehicle, mine or customers, and they've been put behind everything up to several 600HP Hemis, I have a TKO Keisler in my Daytona, I have no problems shifting at 6000 rpm, or down shifting so hard as to lock up the rear end,......but then again I take the time to procure/ install a unit that I know will handle the job, rather than op out at cost and settle for an inferior/ lower performing unit,....the TKO in my Daytona is a $6000 dollar set up right from the start, all the gears have been replaced with chromalloy 4130 steel gears, as well as ugrades to the bearings/ shafts/ etc the entire tranny was built to my request, knowing it would see extreme street/ racing conditions,.....last thing that I want, as well as the next guy is to spend coin, only to regret it later because I didn't research the product.....I know sometimes we rely on the "wisdom" of the supplier, but if you don't question/ research for yourself, sometimes your at their mercy,.......I've been there in the past, and vowed never to be "there" again......I feel for you Mercman, it sounds like, from your post, you "relied" on "their"(?) advice for a unit, or perhaps the $4K was your limit?.......are you running a TKO 500?....if so I'd limit that tranny to a "warm" smblk,....325-375 HP..........trust me, I beat the snot out of my cars, with the intent of breaking something!