Maybe if you gave us a bit more info we could steer you in the right direction. Is this a bike you've owned for awhile, or did you just buy it? If you've owned it for awhile, how satisfied are you with the actual action and performance of the front suspension? If you think the front end damping is fine and all you want to do is lower the bike, then the H-D kit will accomplish that for $100 plus labor. However, if you want both a lowered suspension AND miuch improved fork action (ride, handling, less brake dive, etc.), then spend a couple hundred more and get the monotubes. And btw, don't forget to make sure the rear shocks really are the lowered version (like we told you in that other thread). You don't want to lower the front with a stock height rear suspension as it will adversely affect stabiity. Don't assume when dealing with this stuff, have them measure and verify.
It shouldn't take a large amount of time for a dealer to get the monotubes if that's what you really want. I'll bet they are stocked by a local distributor that your dealer also uses to purchase most of the other aftermarket stuff they sell. If you want to buy them yourself and take them to the dealer for installation, then yes there would be some extra time involved. Some dealers won't install parts you bring with you, so check with them before you do this.
Jerry