well i think just making it strictly "skylines only" is a bit of a wank, as well there are plenty of people on here that are perfectly able to keep up and I don't think you'd have problems with. PhatMirage is a good example and good bloke and was more than welcome last night and his car was more than able to give anybody a run (even though he's now pissed because he read this thread). If you have a performance vehicle with the emphasis on performance and have spent money in doing that, you should be able to come along. Some variety makes things interesting -- we all know how a skyline travels.
And somebody who doesn't know the limits of their own vehicle are probably going to be worse than somebody is arguably in a "slower car" but which has better handling and they know the exact limits of their car so its a bit of a stupid and wanky argument IMHO.
I can understand that we don't want cheap ass rice boxes who'll fly off the first corner and/or pose a danger to the skylines (which is what we are here for), and/or dickheads that may cause trouble, but if they're not any of those categories I can't see the problem at all.
This is also "skylines australia", and not every skyline was produced after 1993 either.. so excluding these because in your eyes they are "shitboxes" just gives an overly elitist, egotistical and wanky attitude. One of the reasons I like SAU is because these things aren't that present here, so don't make it like that.
If people subscribe to the same ethos of enjoying their car for the performance rather than just the looks, they should be able to come.