Command Trac is a part time 4x4 configuration, where the Select trac II is a full time capable transmission. You can run the STII in 2 WD or 4x4 full time should you wish to do so with worry of the drive line wanting to load up due to changes in traction. The Select Trac II will transfer the proper power to each wheel in direct relationship to the traction the wheels are able to provide. I can if needed also transfer up to 100% of the power to a single wheel if that is the only wheel that can provide traction.
If you to the Jeep website they have a pretty good mechanical video the shows and displays the difference.
The Select Trac is the more advanced and benifical of the two, but if the price is right, I wouldn't let it be a deal breaker.
Havent' heard of an aftermarket skids for the KK, but they can be ordered from your local Jeep parts counter.
Good Luck, let us know what you do.
To be up front about it all, if you manage to buy a new Liberty for $7,500 off true sticker price....I will hate you!!
No not really, but I will be very envious of your deal
"If you have a difficult job to do....Give it to a lazy man....He'll find the easy way to do it."