My wheel is not a Grant but my adaptor is. The adaptor was very easy to install and the material and wormanship is great. You have to reuse the horn ring from the backside of your factory steering wheel. Just unscrew the three attachment screws and the old ring is a direct bolt on to the adaptor. This was a nice change from past experiences with aftermarket wheels. Most of the time I had to pray to the horn god to get the thing to blow! Not with this one.
Do yourself a favor though...Get yourself a wheel with a center opening for a horn button so you can bolt on the wheel before tightening the steering shaft nut. You need something to use for leverage. And sticking a prybar in the works is very cumbersome.
If cost isn't an issue.....here's a link. MOMO wheels are awesome and when I hit the Lotto or my inheritence come in....... Seriously, they offer some nice wheels that have a clean (Non-race) look!
http://www.momo.it/accessories.html