Your doorcards are mainly just held on with clips and pulls off, there are 2 screws on the handle though it should all be mainly common sense.
Your Amp wiring you should run up the passanger side where the access is really easy to get under the carpet. There is also a grommet to your engine bay in the passanger footwell if you search on the forum many answers will be found.
Your rev counter might be best to change your clocks to an Si model which has a tacho built in, thought i think they are hard to come by.
Pepper
