Marco,
I've used them myself for a couple of years but changed this year for three reasons, firstly when I moved house they managed to only change one car's details ( I hate to think of the arguements that could have caused if I'd needed to claim).
Secondly the renewal prices this year just weren't competitive any more (I have just turned 30 so other companies start to become a little friendlier).
But finally and what did it for me was the last couple of people I spoke to were just plain stupid and that doesn't instill a lot of faith in me. All other previous dealings with them had been fine though.
But to be honest they all change their policies over the years, I remember using privilege about 11 or 12 years ago because they were the best for young lads with gti's and the like, now they only like more senior drivers with expensive cars (Joanna Lumley doing the adverts............). I found using
www.confused.com has been good this year, saves a lot of time as it does the leg work for you. I don't know how it would fair on heavily modified cars though, I got good quotes on my golf which has non-standard suspension, exhaust, wheels and rear lights-which must seem extremely mild compared to some out there.
Either way, they all make a lot of money out of us.