how many miles are on this car?

is it the original cat?

what is the recent history of this car's operation?

are you the original owner? if so, have you kept your records?

have you consulted them for what has been done to the car?

do you keep a log? do you monitor your miles per gallon? if so, what have been the mpg figures for the last couple thousand miles? can you contrast that with the history of the car's fuel consumption throughout its lifetime?

if so, what do you see?