If you're in sydney, there's a mob called "Competition Coatings" that do ceramic coating. I got most of my engine done and it's done wonders for underbonnet temps. I took my car for a good thrash today in the 30 degree heat, and my temp didn't budge from one below halfway the whole time. The tripple core rad probably helps too... and the airbox.
I'd probably look at a CAI & airbox before you go ceramic coating though.
Bookmarks