The malossi would be best, i would go with something with 2 rings as would be more reliable, if you go for stage 6 u will need to change rings often and prob blow up
no kit will blow up if you take care of it ...use good oil ...warm it up and change rings every 3000 miles and piston every 6000 miles
I wouldnt get a primary gear up kit, get a secondary gear up kit for better top end, depending on how much power the kit will pump with a primary gear up kit it may not pull it therefore loosing your acceleration.
Athena HPR, there powerfull and reliable, Athena HPR kit with a primary gear up kit would be mint because they pump enough power. They also rev high so i primary gear up kit would stop it reving as high therefore more reliable.