Depending on the laws where you live if you can go 35-30% tint all the way around it looks really good with the black paint. 50% helps reduce the interior temps a lot in the sun but it doesn't offer any privacy benefits at all, even 35% like I have is easy to see thru. As for wheels I am not a huge fan of dark colors with black paint but I will be purchasing some soon and don't have much choice in my price range and under 18 pounds. I will most likely be getting the Konig Rennforms from Discount Tire.
As you have a UK registration plate on you can only have the rear windows tinted to any level you want. From the B Pillar forward you can not tint at all as it is illegal and you will be pulled for it. Believe me been there done that.