Right now, the F90-generation BMW M5 is a rockstar. It’s fresh out of the oven and everyone wants a bite. But is it the best way to spend $100,000 on a Bavarian? What about this Dinan-tuned BMW M550i xDrive?

Dinan is famous for making some of the best tuning kits for BMWs on the planet. And their latest for the M550i is seriously impressive. The BMW M550i xDrive is already a very fast car. In fact, it was the fastest accelerating 5 Series of all time until the new M5 came out. So adding a Dinan tune must make t a rocket ship. And it does.

The standard M550i engine is a 4.4 liter twin-turbocharged V8 that makes 456 HP and 480 lb-ft of torque. When paired to an eight-speed automatic and all-wheel drive, the stock M550i is capable of 0-60 mph in 3.9 seconds. But that’s not good enough for Dinan.

BMW M550i xDrive

Using a new tune, a freer-flowing stainless steel exhaust and a higher-flow mid-pipe, the BMW M550i xDrive Dinan S1 makes 606 hp and 635 lb-ft of torque. That’s just six more ponies than the M5 but quite a few more torques. With its lightweight wheels and sticky Michelin PS4 tires, it has enough stick to match its power. We don’t have any specific performance figures but we can assume that it can get close to the 0-60 mph time of the new BMW M5.

The Dinan S1 tune for the M550i costs $14,000, bringing its total cost up to about $98,000, depending on original options. The BMW M5 starts at $103,000. So for only a few thousand bucks more, you can have the proper M5. But would you want it?

The BMW M550i xDrive is more comfortable, more luxurious and far less aggressive looking. It’s a different car than the M5. The M550i is more relaxed, more of a quiet and sumptuous bullet train. While the M5 is manic and psychotic, always with its ears pinned back. So which would you rather have, the BMW M550i xDrive Dinan S1 or the full-on BMW M5?