The SN-95 IRS was designed to be a direct replacement for the live 8.8. They got it right, because they even used the same lift to install them on the assembly line. The whole affair is about 60 pounds heavier than the stick axle, but it saves 100+ in unsprung weight. It consists of a tubular steel subframe, attached in the front to the existing lower control arm mounting points, and in the rear with a bushing and a bracket, which is bolted to the frame underneath the trunk. A picture of the 2000 Cobra R's setup can be found
here.
The subframe supports the upper and lower control arms (with rubber bushings), and the diff carrier (with rubber bushings). Obviously, this makes for a lot of slack. That, of course, is no good when you walk on it, especially with force-fed four-cam power and big sticky tires.
The fact that some cars had 12mm bolts in 14mm holes can't help either!
As I understand it, the wheel hop happens when the diff carrier twists in reaction to the torque (oh god, the torque), and when it does, it rotates sideways also, and this causes the axles to wind up like a twisted piece of phone cord.
I think the biggest payoff for the work involved would come from urethane subframe and diff bushings. The next step after that is the control arm bushings, but they're a lot of work, and to get at the uppers, you have to remove the whole subframe. Bushings kits are available from Maximum Motorsports (
here) or Steeda (
here). MM's website also has their instructions posted, they're a great read to give you an idea of what is involved in the job.
I would avoid putting in 3.73s in the hope of reducing the wheel hop, the larger ratio would probably make it worse. Of course, once you've got a handle on the wheel hop, the gears (and a better limited-slip while you're in there) will give you all the benefits you'd get from putting them in a stick axle. It would make sense to do the gears, the diff, the control arm bushings, and a rear diff cover brace (like
this) all at once rather than having to drop the subframe any more often than necassary.
I found the difference felt like the difference between gumboots and running shoes. You'll feel the little bumps a little more clearly, but it is a small difference and it is definately worth it.
I hope all this is some help, and if there's anything else, feel free to ask here or send me a PM. Good luck. Jim.
irs 
Who has put the differential bushings, the subframe bushings and the irs bracket (the one you weld and bolt in to the back where the spare goes)? This is my next project to reduce the crappy wheel hop on my 04 Cobra. Thanks!
