An LSD would be better, as it lets your car actually work properly rather then just forcing the wheels to be locked up. Since you have a VLSD it will be just fine. If you find it is wearing out/not locking up on you anymore you can save for a 2-way or weld an open diff.

Coilovers have hight adjustment as shocks and springs don't really lower the car a whole lot at all. You can go with D2s, Megans, GodSpeed, K-Sport, Stance, JIC, Zeal, Tein, HKS, etc. It is all the same crap relabled and sold at different prices for the most part. Unless you're talking about Ohlins, Bilstein, JRZ, Moton, or Koni it is probably going to be crappy so you might as well buy which ever is the cheapest. I'd personally recommend Koni Yellow shocks with Ground controls....your car will be ugly and high off the ground but the suspension well function properly and you'll be able to control the car better.

I used an Exedy OEM replacement clutch on my old KA. It held fine at the event (all the slipping problems I had were because of my improper clutch petal).