The plug gap is 0.8mm.
You can get Splitfire platinum plugs from Demon Tweeks for £80 a set. The part numbers ar TP430C and TP392A. If you want to keep the costs right down you can use copper cores, SF430C and SF392A, they are exactly the same heat rating, but need changing more often (the platinum ones are guaranteed for 100k miles).
You don't need a special tool, just a Torx to get the cover and coil packs off, v.cheap plug spanners won't fit because they won't go down the holes.
The plugs do fire in pairs, each coil pack fires two plugs (in different bores), and are wasted spark (fire on the exhaust stroke as well).
As a final word, check them every 20k, no matter what they're made of !!!!!
Whatever you do, don't let your dealer charge £200, it takes 15 minutes to do yourself.......