According to the fellows at Car and Driver , the BMW 135i coupe is a winner when it comes to performance and straight line speed. In their tests, the new 135i managed to get to 60mph in exactly 4.7 seconds, which is about .1 sec faster than the bigger brother, the BMW 335i. Being built on a smaller chassis definitely helps a lot. The 135i is 8.9 inches shorter than a 335i coupe, with 4.0 inches taken out of the wheelbase, and it’s also 1.4 inches narrower.
The smaller size is reflected in the weight savings as well, the 335i weighs 3557 lbs while the slimmer 135i stops at 3420 lbs.
But here is some fragments from their review:
At 4.7 Seconds to 60, Smaller Is Certainly Quicker
In overall length, the 135i coupe (the 1-series is only available in the U.S. as a two-door coupe) is 8.9 inches shorter than a 335i coupe, with 4.0 inches taken out of the wheelbase, and it’s also 1.4 inches narrower. These reductions amount to a weight saving of 137 pounds; our 135i weighed 3420 pounds versus 3557 for a 335i coupe.
Fortunately, there is no reduction in engine size or output. The 135i gets the same 300-hp twin-turbocharged inline six-cylinder engine as the 335i. We clocked a 0-to-60 time of 4.9 seconds for the heavier 335i; the 135i did it in a blistering 4.7, with a 13.3-second quarter-mile at 106 mph. The 135i is seriously quick, but best of all, the quickness comes easily, as the turbocharged engine has enough torque and horsepower to waft the 135i into triple-digit speeds without any drama. Slightly more engine noise and exhaust hum enter the 135i cabin than in the 335i, but the sounds are good enough to forgo turning on the radio.
Much like a 3-series from the Driver’s Seat
Aside from being slightly louder, driving the 135i is much like driving a 3-series. From behind the wheel in the spacious front seat—where there's plenty of headroom—the driver isn’t aware of the 1-series’ shrunken size. The four inches lopped out of the wheelbase are, however, noticeable in the back seat. Subjectively, the seats are slightly larger than a Mustang’s back seat—kids will fit just fine, adults will find it acceptable as long as the trip is short.
Since the 135i comes standard with an M-division sport suspension and 18-inch wheels wrapped with summer-friendly run-flat performance rubber, the 135i rides much like a 335i with the Sport package. There is an almost microscopic line between firm and harsh, but the 135i’s suspension somehow follows it perfectly, even on large, abrupt impacts. The 135i’s structure and suspension never crash or shudder, and aimed in a straight line, the heavy steering and the sense of unyielding structure allow the 135i to approach the composure of the much larger 6-series.
Full review continued here