From (bitter) personal experience I would probably recommend that nobody buys a cheap SuperQuad through ebay.
I recently did so and merely bought a cheap Chinese fake: at best it is a rebadged R7 and at worst it is a worthless piece of junk. Since you have no idea that it conforms to any standard you cannot use these clubs in any competition.
Every SuperQuad I have seen in a shop is all matt black yet mine, and several others that are on auction, has a metallic face. Buy one like this and expect to receive a fake.
I probably can't mention the seller (and since they are no longer an ebay member, what good would it do?) but here are some things to look out for and tips for safe buying.
1./ Ask for photos of the actual club: if it has a metallic face it's probably fake.
2./ Watch for sellers insisting on cheque payments (I used credit card, so I've got a chance of a refund).
3./ If they have 'Private' feedback it's probably for a reason. Avoid such sellers.
4./ Obtain the serial number of the club and check this with TaylorMade. This won't guarantee authenticity but if it comes back as 'Unknown' as mine did, then it's a fake. Don't buy it.
5./ If possible (i.e. the seller is local to you) look at the club first. I doubt there is a genuine seller who would object to this.
Caveat emptor is the best advice. It also shows that dodgy salespeople have been around since the Romans and if they've survived 2000 years then they are not going to disappear overnight. If this little rant helps just one of you avoid being ripped off, then it will all have been worthwhile.