IMHO do the uppipe before you up the boost. The TurboXS basemaps are just to get you started, timing is for 93 octane and you will probably get knock if you just use the basemap off the bat with 91 octane, they need to be tweaked pretty heavily from the get go. They run usually very rich for safety (the stage 2 map I used dipped into the 9's as an example).
With no wideband, the only thing you can tweak really is the boost map along with the ABC/EBC to reach your boost targets, as per the TurboXS manual, and I wouldn't do that before changing the uppipe.
If you have not tuned a car before, you have a LOT of reading to do! Start with the manual, read it 5 times, then also look at Mick the Ginge's tuning guide too, even though it does not cover some of the newer features in the new firmware.