That Malossi variator would require a lot more work then just putting it on, unless you are talking about the varplus, the modified movable cheek for the stock variator, it does help with tuning but it's also a pain in the ass in terms with reliability. I've had the roller weights get stuck all the way out before and had to get a screwdriver to punch them back down.
Porting out the stock cylinder will net you a decent performance boost. There was a very informative post on www.ventilxp.com about porting out the stock av10 cylinder, it gave detailed transfer timings, carb/pipe matching for different degrees of porting AND fuel consumption, but alas, my bookmark of the thread no longer works. Take a look around that site, it's got a lot of very knowledgeable tunes on it.