Theres no "dreaded torque issue" per se. Very simply put, the L67 should have gotten a 4T80-e. The 4T60-e is just fine to handle the L27 into 200k easily, but as stated, at the mileage that car has, either its transmission has already been replaced, or its going to need replacement almost immediately. If it is original, and hasn't gone yet, do NOT expect that to be some kind of miracle and give you peace of mind. It will fail, it is an absolute mechanical certainty. As far as a replacement, for an L27, a sub 75k transmission would be OK from a junk yard (even then that allows for alot of unknown damage to have occurred), but if you're looking for a SOLID replacement HD transmission, I HIGHLY suggest getting a performance rebuilt or updated remanufactured with a good warranty. It isn't worth it otherwise.
Also, besides rarity, the only other benefit to having an SE SC is weight. They weigh, IIRC, 200-300 lbs less (bill had his cars weighed a while back IIRC, he can give you an exact figure there)
Based on that information, I can't see any other basis for a decision besides general condition and price, and only YOU can make that decision.