Let's see... 250hp with a 5-speed and FWD on a ~1997 era GM Vectra platform
with basic shocks and 12" brakes with floating calipers
versus 300hp with a 6-speed and AWD on a ~2001 era Volvo platform that was
credt card debt articles engineered from the ground up for the car with an active chassis system and 13" Brembos on all corners
I'm assuming that cost isn't a factor for you, so why is this even a question?
I love my 9-5 Aero, the engine note is this wonderful growl and for the money it's a great performance package. But it's still a pretty coarse, unrefined driving experience and it's a real one-wheel peel mobile in first through third.
The R is hardly a refined driving experience, but it's still miles above the 9-5 when it comes to handling. In the straights though it's more of a toss-up. my Aero seems to do a pretty good job of keeping up with my friend's R at highway speeds, though the AWD R understandable demolishes me off the line.
I guess the best way to sum up each car is that the R is kinda like a Swedish STI, a slightly nose-heavy but blisteringly fast AWD car with 300hp that really responds well to being manhandled in the twisties. The 9-5 Aero on the other hand is like a Swedish SRT-4, a somewhat overpowered FWD car with the 4-banger from hell that's a bit of a white-knuckle driving experience any time you expect the front wheels to steer as well as making the car go.
As an aside, the S60R also has a phenomenal engine note, though the inline-5 is a bit more athletic sounding than the rumbling, hissing Aero engine.
[redacted and banned]