After you have decided on the make/ model try to read up as much as possible on common problems associated with them. For example the chances of failure of O2 sensor in OHCs is pretty high - ditto for suspension.
Its a good idea to get the car evaluated by authorized technicians - the fees might be a little on the higher side but i would say it would be money well spent.
Just recently i almost decided on a Mar 01 OHC VTEC - after a 10 min check and 15 min test drive the honda technician told me i) the o2 sensor is gone most probably - intermittent yellow light on the dash ii) Suspensions not in great shape (will have to open the assembly to tell anything further, iii) Some problem with the speedo cable etc.
And finally, never believe the dealer no matter how courteous and honest he might sound - the VTEC dealer told me 'apnake charana kharcha korte hobe na' meaning 'You dont even need to spend a penny on the car'
