[Aussie Mike]

I guess different running gear will work better for some uses than others. For an example a live axle car will generally be better on the drag strip than an IRS.

I may get yelled at for this but I think a well setup double wishbone rear end will perform better on the track than a Jag IRS.

For a weekend cruiser and occasional strop through the hils I reckon any of the kits will provide more than enough thrills and enjoyment.

For track days and such some of the kits have a more tunability and track friendly features like adjustable brake bias, bigger brake options, roll bar provisions etc.

Cheers