[Elecraft] Use of K3 and K3S with MK2R+

[w2id at comcast.net]

Hi all, 

I am the proud owner of my first Elecraft radio, a used K3 that I purchased a couple weeks ago. So far, I am very impressed with the receiver, and with how well thought out the features are. As I write this, the rig is on its way to Elecraft for the KXV3B and Synthesizer upgrades. 

I do SO2R contesting with an MK2R+, and will be replacing one of my beloved FT-1000MP's with this new K3, thanks to the inspiration from a friend who complained loudly about my key clicks last year 
. 
I have already picked up a Microham DB37-EL-K23 cable, and I know I need a VGA splitter (one male, two females) to connect the P3 and the TopTen band decoder simultaneously. 
I assume the CAT control should be able to work through the P3 to control the radio, though I haven't gotten it to work yet. (User error, I'm sure.) 


My questions are: 

1. I was planning to NOT add the KIO3BUPKT I/O upgrade, because I figured it's not necessary if I am using the MK2R+ as my DVK. Is that correct, or am I missing something? 

2. How would I be able to tell if the KDVRS is installed? The seller said in his listing that the radio has the KDVRS, but I just noticed as I was writing this that the original invoice doesn't show a KDVRS. Since the seller says he never modified the rig, either his listing or the invoice was wrong, but I don't know which. 

3. When contesting with N1MM and an MK2R+, what purpose would the KDVRS serve? And does the answer to this question vary based on whether or not the KIO3BUPKT is installed? 

4. If some day I decide to also get a K3S as my other SO2R radio, are there any options that would become required in the K3 in order to use the two radios side-by-side sharing a single MK2R+? (Specifically I'm wondering about the KIO3BUPKT and the KDVRS, but do the two rigs need to have those things or any other things in common?) 


Thanks and 73, 

John W2ID