Hi all, lots of questions haha!

Trying to find parts for my scoobydoo from Ken Gilbert manual I found earlier. Just trying to avoid rip off garages! I have a couple of mechanic mates who will do it for me but I need to source the parts. I presume engine wise there are no issues with sourcing jdm parts in the UK?

spark plugs - NGK PFR6G, or anything similar you recommend?
air filter - I need to check if it has already got a rubber one but if not is it worth upgrading to k&n one?
fuel filter - would any OEM fuel filter do? same with oil filter?

Any pointers would be great, going to be an expensive month/2 months as it's going to get coilovers (as it's cheaper than replacing 2 rear shocks), then tracking, and a better alarm. Love spending money on the car

P.S. anyone know someone who can fix the non working digital clock in car as I don't have the equipment! I heard someone on ebay fixes it if you send the board away and he resolders it. Cheers!