I skip read the advert, I was under the impression the car has been mapped for the mods but not the front mount ??
If it hasn't then obviously your first port of call is a mapping session. Its got ppp which is a fairly rich map anyway so if its been run with a de-cat exhaust for a couple of months you should be ok. Just use that fact as a haggle tool.

 

He's only had the car 8 months or so, spent 3 weeks spraying it so most likely only seen the road 7 months or so was standard when he bought it aswell