Re: If you had $5000 to get started wrenching what would you buy?
A little late to the party, but if you're going RWD, go all in. Get a V8 pony car, or like Unkeludo said, a non mustang fox body.
May i suggest a 4th gen, LS powered, 6 speed Camero. I found one with 120K on it, original owner, for 5K. I've been DDing it for almost 2 years. Clutch slave needed replacement last fall, which was a motherfucker to replace with the exhaust being in the way, but I got it done in the driveway. i throw a set of studded snows on it in winter, and as long as there's not a foot of snow down, it gets around fine.
borrow a friends tools. You'll be thrilled at the performance/$ spent, and almost miata fuel mileage. i generally get 23 commuting and upper 20's on the highway. You can store a full set of 275/40/17 slicks in it on your way to HPDE, along with a pop up, and about 200 lbs of tools/gear.
We also have a 5th gen Camero SS, but I like driving this better. It's lighter and just as quick. I'm sure it's not as fast around a road course, but it's still pretty fast.