Take a look at
this post for a summary of what you'll want to do as you start getting onto the track.
Don't bother with the clutch or CSC at first. Eventually you will want to add an insulated clutch line and/or replace the CSC entirely (see z1motorsport's CSC removal kit), but this is not going to be an issue at first so long as you have high quality fluid. Even if you do boil the clutch fluid, you can always pump the clutch pedal back up, so you won't be stranded.
Carbotech brake pads will work well, though I recommend upgrading the fluid in both the brakes and the clutch to at least Motul RBF 600, but ideally Castrol SRF. With RBF 600, you'll have to bleed it on a regular basis, whereas SRF can be left in and basically forgotten for an entire season. With 5.1, you might boil it.
Next you'll want to upgrade your tires. It's great that you already have the oil cooler, that's going to keep you out on the track and save you from a big headache with limp mode!