I wouldn't get a tune first unless it is going to be a while before you finish your mods, no need in throwing money away. Boost control is going to come down to your chosen tuning shops preference basically, they may prefer stock solenoids, 3-port, or an MBC.
A wideband should be your first mod, there are some really nice options out nowadays that allow you to monitor wirelessly via your phone, computer, etc. For the money and time you spend trying to mount gauges, you could just spend that money on a more flexible unit.