Got the ECS set on my TQ. While I don't have any dyno graph's to back it, it feels like there's more "Ooomph" in the higher revs. I used to have to shift up at around 5300-5500 rpm, but now I shift anywhere between 5500 and 6k /ubbthreads/images/graemlins/smirk.gif Anything else I've "Noticed" is prolly mental, as it does seem to rev faster, but not enough for me to be sure /ubbthreads/images/graemlins/crazy.gif
As far as drawbacks, one thing I've noticed is that the lights dim just a little bit when at idle, but as soon as you give it some gas, they come back full blast.
Can't think of anything else off-hand, but try looking around some of the US sites like Vortex, it seems to be a more popular mod back home /ubbthreads/images/graemlins/beerchug.gif