[PrematureApex]

Tires, lowering, and good shocks certainly improve handling a ton. Drives much more like the 335 hatch that it is.

You'll find the "off road use only" labels generally applies to exhaust components that remove cats. The tunes don't override or effect any emissions systems. They are street legal, perhaps except for CA.

But sure, if you're making more power, you're polluting more. But that doesn't make much sense, as if you're using any more throttle than you absolutely have to while driving, you're polluting more. And as you said, you already bought a heavy turbocharged car, so you could have done better in that regard.

If you think you're car is fast...you should get a ride in a tuned N55. And that's not even a "fast" car by today's standards.

But anyway, yeah, lots of improvement to be had on the handling front. The skidpad numbers are primarily a product of tire choice though...so if all you're looking for is more lateral grip, start there for sure.