^ I know this is off topic, but as a 335i owner I recognize that it’s simply not cost effective to spend lots of $$$ prepping the car for track duty.
IMO, the most cost effective alternative can be summed up in one word: “Miata”. Although Miatas don’t have HP to spare, they’re among the most well-balanced, reliable and inexpensive track cars to run and maintain. They also come standard with proper limited slip differentials. These cars do almost anything drivers demand of them: responsive handling, smooth power delivery, trailing throttle oversteer, power on oversteer, trail braking… They’re predictable, forgiving and very fun to drive on a challenging road course. They’re also better in the turns than many exotic sports cars.
You can routinely find race-ready first generation Spec Miatas with extra wheels, tires, spare parts, etc., selling for $10-15k. This is a fraction of the cost of buying and race-prepping most other track cars, especially BMWs. The bottom line is that the Mazda MX-5 Miata is a very capable and extremely cost-effective track car. Consumables such as brake rotors, pads, tires and spare parts are cheap too.
The Miata is definitely worth considering before spending thousands of dollars modding a 335i. Also, don’t dismiss the Miata’s capabilities until you’ve tracked one…
2013 BMW 328i Sedan, 6MT, M-Sport
2007 BMW 335i Sedan, 6MT, Sport (retired)
2004 BMW M3 Coupe, 6MT