For increased reliability you could rebuild the case with a new crank too.
The DR and Polini 43mm kits are my favorites. I have a Polini Top One pipe on my DR and I love it, plenty of low end to make it up big hills and I can hit in the 40's. In my opinion definitely upgrade your variator, the Malossi is excellent if you can get the proper Malossi belt but I have heard the Polini is stronger and works well with any belt.
I think Dean destroyed a Polini variator ramp plate at the last Polini cup race but his Ciao is insane.