Most colours look fine with Tungsten, as long as you get enough contrast with the paintwork.
I don't normally like black wheels but I've run a set of black winter alloys on mine for a few years and they look fine.
Borbet, BBS etc all good options. IIRC the Borbet Y pattern was a factory option for the Mk3 SEAT Leon FR, but in a diamond cut finish and made to SEAT specs. Remember though most of the aftermarket options are 8J width or more in 18 inch, so you'll be stretching your tyres a bit or you'll need to buy wider ones.