My car has only 48000 miles, but has been turboed since 14000.
It runs perfect, just like new.

I maintain my car meticulously, in fact I've changed my trans fluid about 6 or 7 times already, etc.

It's impossible to tell you how long your engine will last boosted, it really depends on how badly out of tune it is and how hard it is abused. If you treat it with respect, maintain it, have it properly tuned and don't hit it with too much boost, it will last longer than you might think.