All Merc T3's were the same. It fit in my Wife's 86 Golf, it will fit in a Jetta.

I did have to persuade the brake line on the passenger side, that's with an ATP manifold.
Oh, and the Merc T3 cold side is the same AR as the Volvo T3, the Merc turbo I picked up had a wanged compressor wheel, I swapped the Volvo cold side over and it was fine. (my machine shop guy just happened to have a tired Volvo T3 laying around)
Brendan