It's a 16g and full boost at 3800 in your case I would be choosing the 517 but it is controlled by the actuator which is not as good for the boost level you want to achieve Plus the 18g does not come in ex housing 6cm And 8cm is a tad big for what you want I was running my 16g at 1.4 bar 307bhp fly and had it at 2bar some times it's an old turbo but suits the 4e and 5e very well