I don't have a VX yet, so I know I can't comment on the AC systems for the VX, but living in Florida for the past 20 years I do know a little about ACs.

My personal opinion is this: Sure you can do things to make your AC better, or delay professional service by using the at-home charge kits, why risk it? The AC system is rather fragile, from what I understand, and something as simple as a little moisture inside the lines can cause serious damage to the compressor.

So in an attempt to delay service by using a few $6 cans of 134a might just end up costing you a compressor, drier, AND the original part that was causing the leak.

If you want to avoid the AC money trap, I would suggest getting some of the UV dye injected, find the leak, then get a shop to fix the part. The at-home charge is just too "rigged" for the prized VX.