vf enginnering only makes a stage 3 set up 12 psi pulley to create 10 psi u can send your charger to america as the bearings are only good for stage 3 only u will def need to upgrade which will cost £150 plus shipping and u will have to get a custom pulley made as vf only make 12psi and no -more but it all depend who maps it as ns racing had a stage 3 vr running 312bhp mapped by a company in england i will not mention but then ns racing started working with a company, sls tuning in germany and they re-mapped and got 357 bhp and it pulls like a train