It took me a long time to learn this, but I don't really like working on what I need to drive. I really enjoy working on stuff that doesn't need to be relied on to get to work.
So, a track car that you can wrench on with no detriment is nice. Because while it sucks to miss a track day, it's not going to make you lose your job. It's also nice to wrench on something that has little or no value so if (when) you screw something up, it's not stressful.
In short, I recommend buying a $2,000 RX-8 and putting a turbocharged four-cylinder in it. Or a 2JZ turbo. Or an LS2. With two turbos.
Alternatively, you can come up to my shop and I'll hand you tools and give you some tasks, because my shit isn't getting done on schedule
