Congrats. Buying 997.1 Turbo at this time is an extremely wise choice IMO; a near supercar level daily drive for practically "nothing."
First a warning: Followed are simply my opinions, if I sound like I think my way is the only way, my apology, I don't mean too. LOL. I get a little too passionate when it comes to Porsche, sometimes.
Exhaust: Milltek is an outstanding choice, but only for certain situations. I am about 95% sure that it's made by same manufacturer as Cargraphic exhaust and re-branded as Milltek. Milltek exhaust tends to be recommended for Convertibles, because it is a rather quiet exhaust. If that is what you are looking for, then it's a good choice.
I should warn you though, that it might turn out to be too quiet for a coupe. And in general, my impression is that people over time tend to wish they have bought a louder exhaust, not the other way around.
I would suggest that you look into Cargraphic also. It's rennteam's "home" exhaust 
(founder of this site, RC, was first to review it click here and has one in his Turbo) and is a no brainer top recommendation: proven quality, outstanding sound. The advantage over Milltek is that it comes with different loudness versions among which you could pick. I believe there are 3 systems in Europe, 2 with TUV approval, and an "Export" version, which is loudest of the 3 (please double check with dealer to make sure I'm providing the correct info).
A few people here have other versions, the one I have is the Export version. All 3 versions are excellent, with the Export being the loudest and has the deepest & most "throaty" tone (according to dealers). The loudest version *might* also be the most free breathing one. This is un-confirmed but if true, it is good for a Turbo engine because of the reduction in back pressure.
I have heard the Milltek in person, but only in a convertible (an ECU tune was causing a loud resonance and owner and I were comparing notes). The Milltek is indeed rather quiet, and doesn't have as much the low frequency menace of the Cargraphic Export version.
There is no such thing as a best "exhaust" system, as sound is by nature subjective and it depends on how loud you want yours to be, but the Cargraphic is definitely among the best there is if you are looking for a medium loud system. An in-person audition is of utmost importance in choosing exhausts, because youtube and sound clip web postings are notoriously inaccurate. If at all possible, I would suggest that you try to connect with fellow Porsche Turbo owners in England and see if you could take a listen.
If you like to read exhaustive details about the Cargraphic Loud exhaust and some other important info, click link in my signature. The one that says "Oh heavenly sound." LOL.
Wheels? Boy have the come to the right place for opinionated opinions. 
I will be MORE than willing to share mine.
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Regards,
Can
997 Turbo + Bilstein Damptronic ( Review ) + GIAC ECU Tune ( Fast as a torpedo & reversible to stock - Review ) + Cargraphic Exhaust ( Oh heavenly noise! )
