How do I fit reclining sports seat in a vw golf mk 4 (2000). Any help or links appreciated. Thanks?

Are the subframes for a golf? If not, you need to get them.

Depending on whether these are equiped with air bags, you might have an issue with the air bag light and fitting the connectors. Here’s a good site for modding your VW:
It’s a free, owner-oriented website where you can search for a similar issue or post your own.