You too can become an 'instructor' with the amount of seat time you have, or by befriending the lead 'instructors'. I see it all the time...
I think Skip Barber's 3-day RACING SCHOOL (not HP driving school) is $4,500-5,000. Because of the economy, there are discounts right and left so I think I heard people getting them for $3K. Bonderant is also a great option but the track isn't as cool, but better cars than Skippy's Formula cars. With as many track days as you have under your belt, I would say go for the racing school. If you had 2 days under your belt, I might say get more seat time first to get the handle of things so you'll get more out of the racing school, but where you're at now, go for it. You'll learn so much that I think it would be more valuable to do the 3-day racing school and 2 track days rather than 17 HPDE days (15+2).
Hmm, if its the rear beam and toe-link vs. suspension, i might still go with suspension. I couldhave sworn your sig said you had V3's a week ago... Anyway, I think controlling the weight transfer with a better suspension like KW is more valuable than reducing deflection with the toe links and beam. I think the car will be easier to drive and more predictable with the suspension (over stock) than the toe link/beam. Having driven many cars from SC, Turbo, NA as well as stock suspension, KW, many others, to stock vs. non compliance beam/toe links, and every combination in between. Go with suspension. FWIW my car has V3s and no toe link/beams (yet).