It's a good few years since I had my mk4 GTI but from memory the Net Optic trims used to look really good.
The OEM trims aren't cheap unless you can pick up a good used set from ukmkivs.
The main issues I remember from mine were the plastic wood cracking despite gentle use and that lovely soft touch rubber coated plastic peeling and looking like a 10 year old banger interior after a couple of years use. No wonder VW changed to the cheapo look interior on the mk5, it must have saved them a packet in warranty claims.
When I had mine the drivers door handle wood trim bit cost £75 when I put a warranty claim in.
So, as above, get some decent quality vinyl, clean up the plastic and wrap it. So many colours and styles to choose from.