Off topic, but I have heard alot of bad things about MAC LT's. I am thinking about the JDM's myself. Everyone says they're easy to install because you install them one primary at the time so you do not have to lift the engine out of the mounts. Fit and finish is also supposed to be good.
My 99 Cobra has HR supersport springs and still hops bad. A good set of springs will help a little. I have always heard that you could calm it down alot but not get it to go away. I spend more time blasting down country roads than down the dragstrip anyway.
I have thought about doing a gear swap myself but everytime I downshift from 5th to 2nd to pass a car driving 45 in a 55 the thought just sorta goes away.
Talk to Joe Lynch, the IRS god.
PS You would not regret the lowering springs after seeing the new look.