i bought the foam base for my sport seats and had a trimmer fit them, worked so well i went and bought a replacement for the passengers front base as well,

ive now done 120,000 km on them and they still look good, ive used liquid shoe polish on the piping on the drivers seat backrest side bolster and it works well.

i would try the kiwi boot polish but would get it nice and hot first to get it to flow easier.