There are quite a few popular upgrades people make.
If it's on runflat tyres swapping them for normal tyres should make it drive much better.
Removing the Clutch Delay Valve will improve how the clutch engages.
Getting the roof motor moved into the boot will prevent it sitting in a puddle of water from the roof drains until it dies - there are a few forum members who can do this if yours hasn't been moved and you don't fancy doing it yourself.
If it is a 3 litre model it will have a Sound Generator that "pipes" some engine noise into the cabin. It has a piece of foam inside each end that can be removed for a bit more volume, but most people seem to reckon taking both out is a bit too much so leave one in until you see whether you'd like more!
Changing the original gear-knob for something a bit heavier is a popular mod as well. ZHP is much better, but there are other options.
Here's a link so you can see what it looks like:- https://www.amazon.co.uk/BMW-25-11-896-886/dp/B0068XM1B4
That is the BMW Part Number in the link, but you can probably get them cheaper from a BMW dealer and that way you know you are getting a genuine one (there are loads of copies, but they aren't as heavy). There is a 5 speed version too. Cotswold BMW or Sopers of Lincoln do a forum discount.
That should get you started! The longer you spend on here the more you will spend. :lol:
