Depends on what you're looking for. From the videos I've watched, I noticed the Eventuri intakes add a nice hint of growl to the cars they've been installed on, as well as an actual improvement in torque and power. It's not overt or obnoxious.
As for exhausts, I've yet heard one I'd install. The aftermarket tends to want louder and a deeper tone, which is the opposite of what I'm looking for. If I get anything, it needs to be something that won't trigger the HOA nazi's in the subdivision as I'm driving out to the main road.
I'm waiting to hear GRP's titanium exhaust. I would really like the weight reduction, but would also want more of a snarl than a roar.
There's also this to consider:
The US EPA has been targeting manufacturers and sellers of emissions defeat devices in a crusade that puts the car hobby at risk.
theautowire.com
Depending on which state you live in, and how aggressive they are at checking things, this could have an affect on aftermarket mods too.