Help me choose parts for my Piaggio nrg power dd 50 2006

Hey im new to this forum but i have had my Nrg for a while now ive done 7000 kilometres i have got it De -restricted like taken the washer out but now ive deciding to upgrade the exhaust, air filter, obviously upgrading the jet but i don't know what size and if you can recommend any good parts that will help acceleration and top speed that would be great.   thanks. [:)]