I've never driven a 7 on 16" wheels so can't comment on that but if you do decide to change to 13" rims then I would go for the Caterham 8 spokes. They are pretty light and don't cost much more than Minators (Minilight style). For appropriate tyres just search for and read a few of the many threads on that subject. For sticky(ish) tyres you can choose between Avon CR500 (my favourite road tyre), Yokohama A048R or A021R, or Toyo R888.
It would probably be sensible to fit adjustable platforms if moving to 13" wheels as you could end up with your sump uncomfortably close to the ground.
You don't say what engine you have but, if its a K-series and you want to do track days, then I would suggest that an Apollo tank is the minimum protection you should fit, especially if you get stickier tyres.
Don't be in a huge rush for upgrades though - drive the car for a while until you decide what the real limiting factors are for you - and then go for it 😬
Yellow SL #32