I have two 98 ZX-7's
My black on black bike is running a 97 ZX-9 rear rim . The brake is different. The 9 has a caliper located above the arm and the stock 96+ ZX-7 caliper mounts below the arm.
Also the ZX-9 Rim has a differnt rotor side spacer than the Stock 7 spacer. ( the 9's spacer is wider. )
You can check out www.exoticcycle.com
for your extensions. ( thats where mine are from ) Johnny can help you out with your needs.
And just so you know these links Have ZX engraved at the front of the extension and ExoticCycle ebgraved on the tops. ( NO SUZUKI STAMPED ANYWHERE. lol )
The ZX-9's arm is the same as a stock 96+ 7 . The axels are identical with the exception of the spacer on the rotor side. My black bike is all stock ZX-7 other than the rim and brake hanger and caliper. My axel is from the stock 7 rim.
Don't forget to add in your extended brake line.
You can make your stock line work with a 6" stretch , but it is not the best option in the world. Anything over that, forget it, your'e pressing your luck.
Also you will need to look into a set of lowering links, or the bike will sit really high up in the air. And if you carry a passenger be aware that the bike will sit way closer to the ground if you do lower it more than 2".
There are a few places offering shocks that are shorter , with stiffer springs to give you the factory ride. However the cheapest one ive found so far comes from www.roaringtoyz.com
and its around $490.
Just some of the things I learned the hard way when I first started to lower mine.
Hope that little info can help you out.