Don't waste your money, there are nothing but bad reviews on these and have been known as the $300 sticker they put inside of your ECU. There are also no legit before/after dyno's back to back to prove these do anything, you can't trust graphs on most sites because they are always going to claim their product makes power.

Save your cash and get a nice intake/exhaust system, and if you're serious about tuning get yourself an AEM FIC piggyback system and have it dyno tuned. I'm sure with an exhaust/intake/tune you could get some noticeable power out of your VX.