Flashing a New Kernel If I'm going to flash a new Kernel with ROM Manager Pro, do I need to reinstall my MOD, delete my data, or delete my cache?  

I am running CM 6.1 and want to flash one of ChevyNo1's kernels but will I have to reload CM and all my data?
No, you do not have to reload or delete anything. 

However do make sure you take a NANDROID backup before you install one of those kernels.  You can potentially get into a reboot-loop that can only be broken by flashing another (lower mhz) kernel or restoring to a previous NANDROID backup.

I went from stock kernel to now running the ultra low voltage 800mhz ChevyNo1 kernel.  I couldn't get it go any faster with ultra low voltage without a reboot-loop.

Basically you will start with the lowest processor speed kernel at a certain voltage and work your way up.  So try ULV 800mhz, if it runs stable at 800mhz, try the 1ghz, then the 1.1ghz, etc.  If you're wanting to conserve battery, then try the ULV kernel.  If you're wanting processor speed, the LV kernel should be just fine.  Your mileage will vary because no two Droid processors are made exactly a like (because these kernels are going outside of the processor's design specifications).