If you really want to get into it you'll have to research how suspension components work together (to understand damper rates and spring rates + more).
But a quick and dirty answer: if you have some "lowered" springs, use something like KYB gas-a-just or Koni dampers. Obviously if you shell out for Bilsteins then you'll get a better ride (provided it's been 'tuned' for your springs/car/usage).
Or throw these in: http://www.otomoto.com.au/p/8475210/nissan-skyline-hcr32-hsd-dualtech-coliovers.html
Hankook RS-3 are actually 200 UTQG rated, Hankook revised the rating.
Advan A050 is a track tyre, so you'd want to get something like AD08 (or equivalent from other brands, RS-3, Z2 Star Spec, RE-11, etc.)
For sale: MSI GTX 970 Gaming 4G
Price and price conditions: $520 firm
Condition: Brand new, never used/installed, all original packaging. Wrapped up ready to go.
Pictures:
Actual item/box is bubble wrapped:
Contact Details: PM
Location: Crossroads/Prestons, NSW
Delivery & Conditions of Delivery: $16.70 Standard Postage (Australia Post Prepaid Parcel Post 5kg Satchel)
$23.60 Express Postage (Australia Post Express Post 5kg Satchel)
Pick up option available.
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Well if it's a daily, then go with their Dualtech (used to be called AD IIRC). You'll still have decent body control. 7/5 on the mate's S15 was fine though Macquarie Pass/other twisties, so I'd go with that.
Too soft for track work, but good for street.
Source: mate had an S15 with them. Good for street/hills but maybe too soft for track.
What car? Evo? Another mate with an Evo 8 got MCA Blue (I think), comfy but high spring rates.
Could be tons of stuff. Is the engine running smoothly throughout the rev range? Have you checked the waste gate?
What turbo? What boost control?
If these are too technical questions, you can browse your state's section for a good place to take it (or ask someone to diagnose the car for you).