Changing Fiesta Exhaust and it's effects: mechanically & on warranty

[FRD6RL]

Hey everyone,

Just got a new tip fitted on the Fez, but as the bit of pipe coming off the rear muffler doesn't quite match up to the opening in the ST rear bumper my hubby's friend (he's a mechanic and did it all) thought it would be easier to remove the rear muffler and run a straight bit of pipe with the tip on the end (I've been thinking for a while now that I'd like the Fez to sound meaner, and this was a cheap and easy way to do it)

She sounds very meaty and sporty when I start her up and while Im accelerating! :evil3:

However I was talking to my dad (he's also a mechanic) and he wasn't very happy with the modification.
He said it would affect the warranty on the car;
and that you shouldn't mess around removing mufflers as the whole engine and exhaust system is designed by Ford to work in a certain way.

Can anyone shed any light on how exhaust mods could affect the car (negatively) and how they could affect the warranty (car is one year old with two left on the warranty)

Cheers, Nic. :newangel: