Sportline is the way to go if you're thinking 190. And definately 91 or newer. I've posted a couple of times as the merits and drawbacks (in detail) and also to the maintenance items, expense, etc etc I've experienced with my 2.6 (search under my username for these).
Summary - great, solid, nice-handling car, needs to be manually shifted around town (or lock out "4"), definately needed sportline-spec rubber (I have non-sportline model), gas mileage not great if you drive fast but these things last and last and last... Cheap to own, very very very few weak build/engineering items worth mention. All around a great car and the 1991-forward models are the textbook example of effective design review and refinement.
Oh yeah - and fantastic MBZ build quality. Haven't wrecked it yet or I'd comment on that too...