Obviously everything Chip has said is bang on
Just like to add my two pennith worth
Really wouldnt want to consider anything else except a Wizard kit for any Nitrous needs
The kit itself is far superior in EVERY way to anything the Yanks can offer
BUT above the quality of the kits, especially as you just starting off in as I know a scarry venture (you can ignore all the horror stories as long as you sensible and get the right advice from the right people

) is the support and backup and knowledge of Trev and the boys at Highpower, the advice and service I used to get was second to none, with the guys up there going out there way to help
TBH I never actually had a Maximiser only the Minimiser which I found adequate for my needs and tbh would imagine that things have come on since my day with the development of the "izers", but I used to run a gear reset count up for the street and a through the gears build up for the strip, ie on the street the build up used to reset on every gear change so if you slowed and knocked down a gear you wouldnt be delivering to much a shot in the lower gears it would start the count from scratch in every gear but on the strip when wouldnt be changing down or finding myself in a low gear it used to build gradually through the gears so by the time i was at the end of third it was full power and stayed that way for fourth and fith, having said that on the Cos I was running 100 shot with no "izer" straight off the line, was only when I went up to 150 shot i thought it might be a good idea lol
As far as the clutch goes ( as any other part of your engine or drivetrain, dont forget these as all will be under more stress) if it already on its last legs Nitrous wont help it last longer, as any performance increase it will shorten its life

but if you really worried about life expectancy of parts go buy a metro (and that aint a Reyland one

)
With the use of an "izer" will certainly help the life expectancy of any parts as brings the power in gradually without a "shock" to components so in fact you can/could actually run a higher shot than you may have actually thought possible and even running the higher shot cause less stress/"shock" than running a smaller shot.
As far as using "izers" you deffinately want to be using Highpower "PULSOIDS" as the name suggests these are built to "pulse" on and off NO OTHER "solonoid" is, indeed the yanks stuff requires the use of a back up "safety" solonoid as they EXPECT their solonoids to fail
Wait till you get hooked on this miracle gas

and get more involved and start thinking of bottle pressures and nitrogen injection etc lol, but that for a latter time
Steve