You're doing the right thing. As good as it is stock, suspension and brake upgrades make a substantial difference in this car. 'Doesn't need any more power; particularly for track work.
Did you get Stage 3 Koni, or JRZ suspension from Dinan??
'Suggestion on pads: Since you got Brembo GT, which mirrors Dinan/Brembo BBK in most respects, you should really consider Dinan's Ferodo pads. They were co-designed, engineered, and extensively tested with Ferodo. Therefore, they're exclusive to, and only available from Dinan (which means they're probably more expensive than widely available brake pads for Brembo GT).
The Ferodo's are phenomenal; whether on street or track. On a hot weather track outting, there is no fade all day. They make ZERO noise and there's little, to any dust; even after being tracked, or used on back country twisties, again and again. The stopping power is very progressive (great for smooth track work) and happens RIGHT NOW!!; with no drama.
You can see from my sig, I have an S3. 'Have given many hard charging rides to local M5Board members; and several have driven it. Besides power and handling, I always get "shocked" comments about the brakes. 'Have no idea what pad compound Dinan/Ferodo came up with, but damned it sure works; every time, all the time.
'Best part is, you don't have to keep swapping pads in and out. Also, you can use ATE Super Blue brake fluid, and only have to change it about once per year. You should ask Fall Line about the Ferodo pads; they're a Dinan dealer and should be familiar with them.
Have loads of FUN!!