Finding the Edge in a BMW M4 Dinan S1

The 530-horsepower tuner special is equal parts Dinan magic and BMW shortcomings.

We call them “The Canyons.” The maze of tight and cobbled sun-cooked and earthquake-shifted backroads that draw ribbons across ridgelines above Malibu. “The Snake,” that’s the famous one. A cambered dance up the backside of the coastal range, topped by a long uphill bowl littered with sportbike parts and dignity. This is where I shook out Steve Dinan’s subtly maniac BMW M4.

The Dinan Engineering BMW S1 M4 had to go to the mountains, I reasoned, because we already knew the car was a perfectly serviceable grand tourer right out of the factory. The M4 reeks of easy, rapid and comfortable commuting. It might have the trimmings, it might hustle, and gloriously; it is sensationally quick, nicely appointed and, make no mistake, faster than its predecessor. But every time I drive one I just feel too damned dignified. That’s where Steve Dinan comes in.

Dinan can’t make the sports car I want out of the M4. He can’t make the M4 smaller, or help that you look up and out, over an airplane dash, past bicep-thick a-pillars. But the engineering shop can work other miracles. They can scythe off unsprung weight. They can make an already well-sprung car corner almost totally flat, and keep a driver’s dental work intact.

They can also add power. Dinan quotes 530 horsepower and 504 lb-ft, gained from cracking BMW’s ECU and adding a cold air intake and a free-flowing exhaust. Honestly? Feels like more. Opening the tap with the long stroke of the M4’s pedal, deferring shifting to the much-improved DCT gearbox—it’s a damned delight. Almost enough to talk me into being comfortable. The miracle that is Dinan isn’t so much that they can squeeze more performance out of BMW’s finest, but that they can do it so naturally. As with everything Dinan does, the upgrades could be factory equipment. They’re transparent. They don’t void your warranty. They’re emissions legal, all 50 states.

This is the Dinan thing. The final polish. The shine we need to see a car without any clouding or hazing from marketing ideas, or limp-wristed OE tire selection, or conservative knucklehead-friendly suspension setups. In the last Dinan setup car I drove, his tweaking revealed the short-lived 1M Coupe for the best handling, most amusing car I’d helmed that year. This time around? The polish reveals something I’d already figured out about the M4: No amount of rubbing on this thing is going to find an edge.