I would opt for a turbo or a 2.0 resp. 120hp and 175nm and 110hp and 165nm. There's not much noticeable difference in power output between these two. A turbo is much cheaper and easier to tune though. With chiptuning you can reach 160-170hp without other adaptations. Beware for the pre 1991 cars, they have a very bad rep regarding electronics/wiring. Halfway 1990 Volvo upgraded the wiring.
If you opt for a n/a 2.0i go for 1994 onwards, as the 1992 and 1993 2.0i engines use a LOT of oil. You can identify those engines from the red oildipstick. The better non oil using '94-'95 2.0i engines have a green dipstick.
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