Haggling... you need to understand how salesmen work which is (a) do you have a compelling event to act (b) can you afford it.
Before I was involved in sales, I though there was no structure... Big mistake. In my Company, I've never seen such a scientific approach to understanding what was going on and with premium main dealers, am sure they are all highly trained & whenever I buy anything, because I know the key words & answers they are looking for, ensure I help uncover them....
So, you're after some tactics...
1. if you feed the sales(person) the two points mentioned above in a subtle way, they will follow you around like a lapdog who wants a bone
2. Step two is to remind them you have a choice, simply by saying you've been looking at an AUDI TTRS & debating whether to get a new one as you have a friend in Huntingdon AUDI who can get you a good discount if buying for cash (mentioning discounts here prepares them that they will have to haggle hard & you have the money to push the boat out)... Maybe you've looked at a Merc or tempted by another Porsche...
3. Step 3 is never let them know what you really want, appear undecided, looking at a M3, diesel 335 convertible ... Oh & u like the shape of the Zed but it's impractical.
4. Keep referring to buying a Zed as more from the heart & u need to be practical... & see what movement may be available.
5. With 3/4 different vehicles of interest, ask which one could they offer the best deal on... what's their best price
6. Have other cars you are going to look at at hand and discuss why their cars are sooooo much more expensive...
Remember, you will pay a premium though if you know the market prices, get a BMW extended warranty and are approx £1000 away from what you want to pay, mentioning you'll close the deal there & then or you'll walk & look at something else is a difficult one for them to swallow if they know for definite you have something else lined up.
Go play & let us know how u got on