Better brakes are ALWAYS a good idea, no matter whether you are running a little 998 or a turbo 1275.
and lets face it if you're going to the effort of fitting any type of engine mods you will be driving quickly and thus better stopping power is always handy. Don't be an ass and proclaim you wont need to uprate the brakes, at the very least a full brake service and inspection is advisable.
Now, aimed at the OP:
I would do some revision to be honest, it doesn't sound like you have much experience with forced induction, I would do some reading right down to the basics of what forced induction actually achieves; key words to search would be volumetric efficiency, that and what you need to do to the engine in order to run a reliable turbo. David Vizards "tuning the a-series" book is excellent at all mods for a mini engine and will provide 99% of the information you require.