These are what parts I installed or are planning to install for occasional tracking on my Z.
1. Need the most comfortable clutch/flywheel that would compliment my GTM SC.
OS Giken Grand Touring, will handle an SC setup easily and will be comfortable for a DDer.
Product
And if you're in there already you should upgrade the CSC as well.
2. SS braided hoses and brake fluid (maybe pads)
I use the Z1 lines but I think any lines from decent manufacturer will work.
IMO you really, really, want to upgrade the stock pads and fluid. More important than anything else. These are known the overheat/fade and cause you to lose your brakes, a very bad thing on the track. I use carbotech XP10s, XP8s are popular too. Some recommend doing a XP10s in the front and XP8s in the rear. For fluid I used RBF660 (overkill) I am planning to go to RBF600.
3. Want to buy the best duct that I can retrofit my front bumper with, to allow ram air for the oil cooler...GTM seems to have done these but I can't for the life of me get Sam to sell me these things.
Best is the DIY ones though I think Stillen offers a kit.
4. Possibly a bigger oil cooler, this isn't a must have at the moment though.
I use a 24 Row for my NA engine and it works well on the track peaked at 240F @ 80F ambient.
The event is on the 21st. I'd like a quote for installation as well, else, I'll just do the install myself.
Pads and fluids are the only required upgrade, maybe a larger ~30 row oil cooler since you have a SC.