Aboclute and TPM are both great orgs
I've done one TPM trackday at Monticello last year. I thought they were good but not great. I dunno but I guess I got spoiled at Tonystrackdays. If you've never done a day with them, give them a shot. Might be a little expensive, but I got more track time, learning, and more help from riders/instructors.
Skip those mods. Your mods should be trackfarings and save up on tires and seat time.
Seriously..if you REALLY feel the need to spend money on the bike other than seat time, get your suspension done. Those mods will be worthless without them and money much better spent.
Get your bike set up for your weight before you hit up your next trackday. It shouldn't be more than like 40 bucks. I'm not talking about ohlins or racetech stuff. Just the simple set up will do for now.
IMO this should be your priority list before your next trackday:
1. Leathers - 1pc or 2pc doesn't matter whatever fits, and is in your budget...
2. Suspension - set up for your weight
3. Tires - decent tread life left
4. Maintenance - Go over the bike and make sure everything is good (chain, oil change, brake pads, fluids, controls, etc.)
4. Read up - On any and everything track related, especially Body position, throttle control, and finding the right line.
I think that's enough for now....