Possible Speedometer Rollback
 

We recently bought a Pre-Leased 2006 Jetta with supposedly 33000+ miles on it. Below are reasons that I suspect a speedometer rollback;
1. Second day we had it we heard kind of a rattle toward the back of the car. Took it back to the dealer who had to have the converter replaced at his expense at the nearest VW Dealer. Turns out that some ceramic was loose in the converter.
2. All four tires have been replaced with one brand on both front and one brand on both rear. Ordinarily I have had tires last upwards toward 60K miles. Wonder why they've been replaced before I bought the car at 33+K.
3. A couple of other minor things but otherwise the car is in good condition.

I did a Carfax before buying the car and the report authenticated the mileage but I've heard that a speedometer can be rolled back via some sort of special electronic tool before the final listing in Carfax and am curious if anyone thinks this could have happened to me.
Thanks for any input or insight.

Shiney tires sell cars.

The dealer probably just threw new ones on there to make it more sellable. Did you buy from a reputable source, or an individual?

Thanks. I bought the car from a very reputable dealer.