It's not really that it's a golf that makes it awkward for fitting bucket seats. There are several ways to fit aftermarket bucket seats, you can try and find seats that use the factory mounts like the standard seats, or get tailor made frames for the golf mk4, or you can weld in generic mounts for the seat's frame to bolt onto.
I'm guessing it's not a track car and doesn't need to be FIA or MSA compliant so you'll be fine with any of the above options.
