I'm currently wrestling with a similar dilemma with regard to taking my car on track. It's expensive to track a McLaren, particularly if you have OE brakes, and even more so if they're CCBs. The OE pads are relatively soft, which protect the extremely expensive rotors, but OE front pads are $1200 and only last a couple of days on track. You can get cheaper pads that last longer, but then you're increasing the wear on the rotors. There are other costs too, insurance since the car is high value, track inspection if you have a warranty on it, and Corsa tyres are only good for a few track days too. It's also somewhat problematic to do 2 or 3 days a year, since most of the clubs are geared towards tracking at least once a month, with the focus on training and improving lap times. I don't give a crap about my lap time, I just want to enjoy going fast in my car and to take it beyond what I can do on the road.
Part availability is already an issue, and parts are also expensive (roughly twice as much in the US as in the UK, and they're not cheap in the UK). Reliability on track is fine, just the usual potential issues with increased heat, consumables, etc.