I've had experience of both.
Fitment:
Viper is a mess & looks crap. The bracket is flimsey and the feed is a pain in the ass to get down to the grill.
Maxogen took all of 5mins to fit, bolted to the slam panel and the design is bespoke to the car, i ran it without a feed.
Performance and noise:
Viper: Sounded ok, lost 2.3bhp and 4ft/lb torque
Maxogen sounded amazing, power across the curve and a reduced emphasis on the 5k kick.
didn't do a power run before and after, but its just a nicer bit of kit
For the money...No IK is worth it, A panel filter will suffice, but i got mine for penny's so it was worth it's wait in gold.