The only models I can think of is the Buick Grand National and Regal but they stopped production in 1987. And as willwern stated the Grand Prix Turbo in 89 and 90 with a 3.1L pushing 205HP and a managed 225lb-ft torque. Here seems to be a pretty good web site on the Grand Prix Turbo http://home.att.net/~aldridgec/
. I think the car companies mostly found out they could get more power and less stress out of a bigger engine than trying to beef up the small one. Like the turbo 3.1L only pushed 205HP which is very repectable it predicessor the 3.4L pushed close to 210HP without the stress of the turbo. Another good example is the new GXP they are putting the V8 that is going to push close to 300HP and it is not going to have the stress of trying to really beef up the V6 to get close to that.