It's very much personal choice here. I've never used a repair kit as I've not wanted to take a chance so opted for a space saver. In fact, recently, I've replaced the space saver with a full sized spare! Either option compromises boot space to laughable impractical levels.
Welcome to the forum and to Z4/E89 ownership. The car looks in great condition. Private purchase or from a garage/mileage? (Just curious). Auto or manual? As has been mentioned, Salmon Relays are the cheapest and easiest preventative work. 5 Minute job and available from your local dealer for...
Welcome. You're likely joining a big list of folks who fit the midlife crisis category. Nice looking car. That blue is great when polished and in the sunshine. Are those alloys 17inch? They look spot on.