Both induction and exhaust could/would give you a more aggressive noise. Induction tends to be a little more subtle, obviously the noise coming from under the bonnet and also tends to only be noticeable when planting your foot down. This could be seen as the major benefit as when you're just cruising down the motorway it makes little to no difference to noise.
Exhaust can be a tricky one as the sound can vary from exhaust to exhaust and unless you find someone with the one you're looking to buy for you to listen to its pot luck whether it sounds like you want. Less risk with the quieter exhausts as the change is less extreme so you're less likely to dislike it. Benefits of the exhaust are potential visual improvement as you can chose the style of the tips, you usually save weight and you'll have a system that will last for life.
Both of the above 'can' improve power but on an NA motor you won't notice the difference so in my opinion I wouldn't even consider that aspect.
