Can the 135i keep up with its sweetly ///M-tailored counterpart, the 1M, at a track like Laguna Seca? With some upgrades, it can...while remaining a comfortable daily commuter.
Our benchmark for comparison is the BMW 1M lap time of 1:43.31 at Laguna Seca established by MotorTrend's Pro Driver Randy Pobst. That's pretty quick - in the E92 M3, Randy managed only 0.35 seconds faster.
The 135i just needs a new suspension, camber plates, LSD, wheels/tires, and better brake pads+pistons. Adding power or installing wider fenders are not necessary to match the 1M!
Properly sized brakes are preferable however... Currently, the car needs to be braked earlier than necessary due to lots of brake fade and pedal softness/dropping - at least quarter of a second in some corners. A bigger brake kit is the next upgrade this car really needs! And of course, more seat time
There is another 2 good seconds to squeeze out in this current setup especially once the brakes are sorted.
My list of upgrades to match the 1M:
-Ohlins R&T with Swift springs
-Quaife ATB Limited Slip Differential
-All E92 M3 arms, bushings, front sway bar
-Vorshlag camber plates @ -2.4
-Apex EC-7 18" wheels, 8.5" front / 9.5" rear
-Hankook R-S4, 235 front / 255 rear
-PFC-08 brake pads
-Racing Brake stainless steel pistons
-Castro SRF brake fluid
I must note: As fast as the 135i can be, it will likely never be as fun to toss around like the 1M...
