Hi there, about to sell my 2004 Mk V GTi (Red, 5dr, DSG) to get a manual 2007/8 one or 2009 Mk VI and The Doc mentioned that
NOT p/x’ing might help me negotiate an extra grand off from the dealer on the car I'm buying... wow, did not know that!

It got me thinking – what is the best advice on buying from a dealer, especially on Finance? Tried searching the forums, but no joy.
Anyone got any top tips for:
- best way to negotiate with the dealer – especially on APR % (or ‘new’ car cost / part-ex value)
- are upgrades a good thing to negotiate on ("throw in a new Sat Nav, Mr Dealer, and it's a deal")
- playing dealers off against one another
- do extras like Sat Nav, MFSW and Xenons etc add much value to a car?
- best time to buy from a dealer (month end? And I heard Sundays were best?)
- any other good reasons to p/x OR not p/x (i.e. regards minimising the price they’ll then accept on the new car)
Apologies if there's already a thread like this - pls shout if so. Many thanks.
And obviously I did some Googling too – the sites below are the best I found – but any UK/ VW-specific, real-world insights would be great.
http://beatthecarsalesman.com/school/step5-10.htmlhttp://www.carbuyingtips.com/car5.htmcheers.