I'm looking to change the turbo on my forged 2.5 from a md555 450 to a gt3084 so I'm having to have the exhaust modified for the external waste gate. Once fitted will it be safe to drive before I can get it in for a map tweak?

 

if you keep it on the lowest spring and don't connect the boost solenoid then do your best to drive it off boost you'll likely be OK. It's difficult to say as a lot depends on how it was mapped for the first turbo - have you checked with your mapper?

 

JGM mapped it, for its current set up. I've been trying to get hold of Richard @ Zen to book it in for a remap, but I know he's been busy.