How much should I aim to get reduced off the price of a used car?

When making a cash offer to a franchised dealer for a used car, what would be a reasonable percentage deduction of the asking price to suggest?

Is the stop start system in my Honda Jazz more trouble than it is worth?

I have some doubts about the benefit of this facility. Every time I come to a stop with foot held on the brake the engine stops and release the brake and the engine fires up. This means that the battery...

Will the stop-start system on my Fiesta damage my engine?

Does the auto start/stop system wear out the engine quicker and turbo? Also, what kind of battery does it have? And has the starter motor been made stronger to within the stop starts? And what the system...

What stop/start battery do you recommend?

What stop start battery would you recommend for my Skoda Octavis vRS? Prices seem hugely variable, as do warranties. How do I choose?