Gilera DNA125 tuning

I'd like to push my Gilera DNA125 a little (acceleration + top speed)


To start I was thinking about placing a Malossi Multivar.  In the description it says 'better acceleration, better top speed'.  Does this vario really make a difference in top speed?  Is it useful to add the Malossi kevlar belt?

Next I was thinking about a Scorpion exhaust, though for the same money you have a 210cc bore kit...  When applying that 210cc kit, do you need to change some other stuff too? (carburettor, ... )