I did indeed win the Vararam including installation at the 2007 CAC Cruisefest. Thank god it included the installation because as I've said before (check the other posts on Vararam) if I had done the installation myself it would have taken me a couple of days and at least 2 pints of blood. There are a couple of tricks to make the job easier but if you don't have a lift or way to get under the car it may be easier if you remove the hood.
I've had it almost a year now and have never raced the car so don't have any way of compairing times however by my SOTP it feels much stronger at the higher rpm's and the sound combined with my Corsa Touring Tiger Sharks is awsome. Interesting to note that on a 350 mile trip in the high altitude mountains from Pagosa Springs to Denver when I decided to behave myself and drive pretty much speed limit I averaged 31.4 mpg which blew my mind. I had never gotten over 27 or so before. I did install a pair of Z06 screens in the duct openings to keep from sucking up small children and economy cars but with only 2-3k miles on the system (my annual mileage) I haven't yet checked the filter to see how much dirt it is collecting. I too have a concern about the hydrolock potential but I haven't driven my car, nor would I, in a heavy rainstorm or dirt roads. Others have voiced this concern but I have never seen a posting or talked to anyone that had first hand knowledge of such an occurance.
The one item you might watch closely when you install your system is that the filter section seems to sit about 1/4" too high so that the bridge to the throttle body has a tendency to work loose and rise off the anchor pegs on the radiator cover and rub agains the hood insulation pad. Others mention it with their installations but I haven't yet attempted to do any modifications to make it fit better.
In summary I like the system, I keep reading that it is probably the most functional ram air system on the market for the C5, it looks great (I like to show my car) and if it ever has problems I still have all the original stuff and can convert back easily. Advice, take a look at a completed installation and talk to someone who has done one before you jump into it. Good luck.