[av.auto]

My car is a N54 135i with about 60k miles on it. Prior to my ownership, this car was heavily tracked (think 10-12 track days/races a year), and the wear and tear showed up on the turbos as the seals started to leak. I replaced the cores and rebuilt the wastegates with VTT's OEM replacement CHRA's and their upgraded wastegate kit. Upon my first track day at Buttonwillow (and around 3k street miles), the new cores started smoking heavily, and my front turbo wastegate is stuck... looks like I'm back at square one.

The car is still a street car, with about 10k miles a year on average, plus anywhere between 3-4 track days a year. I'm considering options ~$2000, and currently have OEM replacements, Pure600/Stage 1's, RB Ones, and DAW turbos on my radar. Aftermarket turbos seem interesting as a way to tone down the mid-range torque and pull to redline on track, as well as keeping turbine speeds lower with a conservative boost target. However, my biggest concern is reliability (I plan to have the car tuned fairly conservatively to favor seat time) as I really don't want to be swapping turbos on a regular basis. Wondering if I could get some anecdotes for longevity with aftermarket turbos or advice on what direction I should go. Thanks!