I echo Ry's opinion. I'm biased towards things that both look good and provide utility. I don't mind bodykits, as long as they're not too obnoxious (too bad many are, based on observation) and are backed up with power improvements that offset the added weight of the kits and then some.

Aftermarket exhausts are a mixed bag. A lot of people put 'em there without doing any other power improvements just for the sound and looks alone. Kaya usually, at first glance, medyo negative reaction agad ang marami, lalo na kapag yung muffler ay tipong sobrang laki at maingay.

With regards to that Mazda, same. If the car has the actual mods dictated by the stickers, it's good. The bodykit's appalling, though. Would've been better if the car stuck to a look not far from a Mazdaspeed 3.