I have a '95 850 GLT that I bought on the Euro delivery program, and an '86 740T with 156,000 miles, Bilstein shocks and the original turbo. The 850 has the sport chassis and 5 speed.
In overall appreciation, I would give the nod to the 740T. It is a blast to drive on my twisty roads. One of the tings I like about the '86 is the fact that if a timing belt breaks, you simply replace it, re-time the motor and move on. With the 850, not so simple. I should replace my belt soon, as it has 61,000 miles on it.