In terms of performance, the model of the 2010 Volvo S40 and V50 that most impresses reviewers is the T5 AWD R-Design with its standard six-speed manual transmission.
The T5 offers 227 horsepower from its 2.5-liter turbocharged engine, coupled with 236 pound-feet of torque, which is all available at rev ranges between 1,500 and 4,800 rpm. This prompted quotes such as “launches off the line” by Car and Driver, who also claim “great highway passing with no noticeable turbo lag.” Kelley Blue Book chips in, noting the “turbocharged engine brings the little S40 [and V50] to life.”
On the other hand, the naturally aspirated 2.4 liter inline-five with 168 hp and 170 pound-feet draws quotes ranging from "perfectly adequate” (courtesy of Edmunds) to “unimpressive, especially up long grades,” according to ConsumerGuide.
A choice of five-speed manual or five-speed automatic is still offered with the base engine. Kelley Blue Book advises, “go easy on it and the stick can be slid from gear to gear with barely two fingers," and when talking about the manual and of the automatic, they find it “seemed to work quite well.”
Regarding the suspension, Edmunds comments that “most drivers would be more content with the standard setup as it offers a more livable compromise between performance and comfort.” The firmer suspension of the T5 AWD R-Design “makes for an uncomfortably stiff ride,” complains ConsumerGuide. Cars.com is happy overall, asserting that “curves produce only modest body lean, and the sedan corners crisply.”
As can be expected, the all-wheel drive hurts fuel economy, even when it isn't required, affecting mileage by up to 2 mpg. However, in the opinion of reviewers, this is offset by the efficiency of the turbo engine that offers all that extra performance.
Edmunds reports that “Volvo predicts a 0-60 sprint of 6.7 seconds with the manual and 7.1 seconds with the auto” for the T5 AWD R-Design. Estimated fuel economy is 20/26/22 mpg with the manual and 19/27/22 mpg with the auto. As for the base 2.4i model, Edmunds notes a 0-60 sprint of 8.5 seconds and estimated fuel economy of 20/31/24 mpg for the automatic.