Looking to buy a nismo
 

I'm looking at a 2011 red nismo 20k miles it has stillen cia and after market exhaust. It has drilled rotors and stop tech pads also. Kenwood head unit touch screen and sub woofer and back up camera. It's a really nice car well maintained and has extended warranty to 70k and 4 more years from Nissan. He wants 28k but I think I can get it for less. It does need tires and it looks like that's like $1300 at least from tire rack.
Any thoughts?
What should I look for before I buy?
I was gonna take it to the dealer for a check up and see what they can find.