An electric oil pressure gauge is critical. It's just as critical at stage 1 as it is elsewhere (you do the same oil system modification).

It's basically just to warn you when you suddenly spring a leak and you don't ruin your motor + turbo.

Would I would do differently if I were to go back from what you have listed would be getting a wideband RIGHT AWAY. Yeah, it's a couple hundred, but wouldn't you rather boost happy and keep your engine from blowing up? The blinky light gauge is useless. You can blow your motor when it reads "rich".

Joel Baldridge, ASE Certified Master Technician, Audi Certified Expert Technician