hi kane, ive also got a 07 cpi aragon gp 50, only getting bout 30 outa it. you can buy a new de-restricted down pipe exhaust system! im gona try and cut my original exhaust and remove the restrictor and get her welded back up! il let you know wat happens. also you will need to replace the cdi box with a performance cdi box with no rev limmiter for max performance they cost £35. this is a few things ive found out. if you get any ideas let me know mate cheers johnny