I’ve just fitted a Welsh Willy kit to my 97
It comes pre cut with fitted guides, so just a case of fitting.
It was very close to the limit on my gun and once settled I ended up cutting half a coil off and dressing to bring down to 11.4ftlbs.
TbT kits are good as well, just fitted a short stroke kit to the piston, feels nice on test firing but will need to try properly at the range when it opens again.
I do fancy a 99:will,probably get one in the near future.