The dealership is always a rip off, I'm convinced every one of them sabotage your car so it's just never ending problems. If you have some mechanical abilities I say do the work yourself. The turbo replacement is not that bad and you can repair the turbo oil leak when you replace the turbo. IAG Performance offers a kit that replaces the stock hard lines for the turbo oil feed with braided lines. It should only take you a few hours to replace the turbo. Get a can of Aero Kroil and soak all the bolts for a day before attempting anywork and be ready to extract snapped and rounded bolts. If the secondary air pump is giving your issues I suggest deleting it, it's useless. You can do all the work it's not that hard it's just time consuming.