Check out these broken parts. http://geocities.com/crosley_az/brkepart.htm

 

Yup, I had one similar to the one pictured on the lower right in my 92 RS with a 305 and no nitrous.
That is why I will never put another one in my car. I have been through 5 units and the car only has 78,000 miles on it. All hard parts breakage.

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LOBC-- SS-84

92 RS Heritage package with a 305 3" high-flow cat and pipe with a Dynomax 3" in dual 2 1/2" out.

84 El camino- 383 CID, Performer RPM, GMPP vortec heads, Holley 750 D.P.(0-4779c), Crane Energizer 274,Dual 3" Flowmaster 40 Series Exhaust, Turbo 350 (375b), TCI 2500 stall, Richmond 3.42 gears, PST Poly graphite Suspension bushings, PST steering linkage, PST springs, Monte SS sway bays, Wheels from a Third gen(does that count?)

 

You can run nitrous if the transmission is built right and you use a 9.5" or 10" torque converter. The stock TC is way too heavy and is very hard on parts because of this (as you have already found out). I have a customer who owns a 1985 Vette using nitrous (200-250 shot) using the Continental 10" with anti-ballooning plates 2,800-3,000 rpm stall, 3.33 rear end gears, shifting at 6,600+ rpm and he is running 10.90's at 126-128 mph in the quarter mile. I have quite a few transmissions out there using nitrous. I have problems with 700R4's just like anybody else, but I have never had anything break (Not Once) when using a 9.5" or 10" torque converter. The aluminum drum, input shaft, sun shell, output shaft can handle only so much. With the wrong valve body kit and or a stock 12" TC with any kind of horsepower things just will not last.
Hope This Helps!!!

 

The 700 parts in the pics were behind stall speed converters.

I work for a small tranny company and don't know much about the 700 trans though.

Seems like a person can break most any part.