Is it this one?:
http://adcache.boattraderonline.com/6/5/4/69512354.htm Unless you're handy and have some extra time, I'd have the dealer do the install and include it in the price/loan. That assumes they have done a few and know what they are doing. That way you have a stock system that is also under warranty.
I'd get the rear tank and locker plumbed in and wired permanently. If you ride a lot you'll get tired of pumps and sacks real quick.
See if you can get BoatMate to ship and retro a 5200 lb axle on the trailer. Then just permanently stow about 400-600 lbs. of lead around the boat.
With stock ballast plus the lead this boat puts out a very respectable wake, especially for the price. I rode about 100 hours in my friend's LS. It's a great value.