You forgot to mention that the rx8 is na and your skyline has a turbo hanging off its engine. Mazda also had to rush the ecu mapping with their rx8's simply to get the car out the door in time. Some guys on rx8club.com have been playing with the ecu mapping and have managed to get an extra 50 rwhp out of the car. The car has an exhaust done to it as well, but thats still over 280 @ the fly, from an NA car. The fact remains that they are petrol guzzlers, but the bad rep about them isn't true, its not the cars fault but the owners. They abuse the crap out of the car by revving its tits off from a cold start and then bitch and moan when their car doesnt run properly. Its a known fact that you have to let the engine warm up and cool down appropriatly, and because they have oil injection they use up more oil than other cars of that class. Not really sure if this is detrimental to the conidition of the engine, but synthetic oils shouldn't be used for any rotary engine, its recomended to use natural.
That video of the fd against the r33 gtr in japan, thats the 255hp rx7, later models like the rz's and rs's have 280hp claimed and the turbo reliabilty issues are solved as well.