My roommate has three, count 'em, three Dodge Stealth TT's in the garage. My poor little GN is surrounded. So, right or wrong, I've become a bit knowledgeable about these things.
Yes, they are heavy. However, my roommates' 1996 Stealth TT (one of only 6 made with silver paint) ran 13.08, bone stock down to the air filter. As far as we know, he owns the record for the fastest bone-stock Stealth. He recently acquired a 1995 Stealth TT that does not have 18" rims nor a sunroof, which is rare for those cars. He thinks that he can get it to run faster than 13.07, because it weighs less. I think the statement "13's are possible stock" is a bit pessimistic.
The weakest links, from hearing my roommate talk, is the transmission and the clutch. My roommate has several spares for his "probable-11, possible-10" never-ending project car.
My roommate's screen name on 3si.org is "Joe G." He'll answer any questions that you might have. He knows a LOT about these cars. Just check out his web site - you won't believe it. And, these links aren't even the whole thing.
http://joeg.mi3si.org/index.html
(notice he has his own page on 3si.org)
http://joeg.mi3si.org/102701_MI3S_Gathering_at_Lapeer_Dragway.html
(the infamous 13.08 run and my GN, the data on the GN is way out of date)
http://joeg.mi3si.org/3S_Production.html
(a BUNCH of exhaustive research on 3SI production volumes, options, etc.)
Good Luck,