negotiating

My 4 year finance deal with MB on my C-Class Saloon is up in 6 months so I received the "your options" paperwork last week. I'm very tempted to give it back and take out a new deal on the new coupe, but I'm going to need some buying power to get the extras I'm after. I tried carwow.co.uk just...

What's the most you have negotiated off a car? My current Mercedes was advertised for £7300 and I paid £6850 2.5 years ago. What's the most £ or % you have negotiated ? (Looking to buy a new car soon hence wanting to know what the 2nd hand car market is like now)

I'm currently in a negotiation stage for a new or nearly new smart diesel. If I place a factory order now, delivery won't be until February and therefore one may as well hold off another month and wait until the 12 plate comes out in march. Alternatively, if there's something sitting somewhere...

OK, so given the price of the car i am about to negotiate on i'm happy to pay sticker price. On the basis I am not getting finance with MB, I trying to think through what else I can "throw into" the deal to sweeten it on my side. Obviously fuel, any tyres needed, update servicing, road tax...

I was just wondering if anybody has recently had any experience in negotiating the price of a used vehicle with a MB dealership. Today, I offered £17,000 for a vehicle which was priced at £18,490. I thought this was a quite a good figure to start off a bit of negotiation but the dealership in...