What makes it chav out of interest? Never heard of a red car being called chav red?
It's quite hard to categorise exactly, obviously certain cars in red aren't chav. A red ferrari for example wouldn't normally be descibed as chav, unless it had been chav'd up, which is unlikely as the average chav can't afford a ferrari.
The GTI is already veering towards being a chav car. It has all the hallmarks a chav looks for when trying to impress their mates, it's fast and relatively cheap, for the performance. and it's easy to pick up after market add-ons from Halfords. Also think about all of the old GTIs kicking around that have awful body kits, lowered suspesion etc. They sully the brand, and push it towards being chav.
This isn't just limited to GTIs, think Subaru Imprezza, Focus RS, etc.
What's makes these cars even more chav? A colour that makes them stand out so they can show off even more, and red is the most common colour that does this.
By the way, I have a 7.5. I would love to have it debadged and wish it didn't come with those awful chav alloys. The problem is, it's such a damn good car I had to get one. My next car will be a Golf-R, much more subtle IMO.
Just my opinion, I understand a lot of people will disagree.