HT leads will cost about £70ish for some good mantacor leads, the stock leads are thin and can cause ignition issues, this is rather bad for rotarys.
For lots of maintainace help and some performance ideas check out this site:
http://www.1300cc.com/go to the 2nd gen section at the top and have a look around

For an FC workshop manual with all the other mantenance things check this site out:
http://www.importworkshop.com/mazda-rx7-rx8.htmlclick on the FC series 4 manual. The series 4 wasn\'t in the UK as we got the series 5 only, but all the parts in the series 4 are basically the same, just some parts are on the other side of the car cause the series 4s were LHD