Information sources for used cars

Hi all

I'm looking into buying a used car. does anyone know where is the best place(s) to get information on spec level of cars and service information?

Is there a site that tell you which spec level was the highest for each car released onto the market.. e.g focus : Lx, connection, zetec, titanium etc and what features were with each model.

Can anyone remember the name of the car service site where you picked your make and model from a drop down list, entered you mileage and it told you what needed to be done at the next service... like plugs, timing belt etc. (was something like mycarservice.ie)

I have honest john on the list

also suggest any other helpful site any other sites like Cartell, mywheels and the revenue ownership change
(i cant post any links)

the guide to buying thread is over 100 pages to trawl through, its gone too big, could do with a pruning

Thanks guys