Needing tips for my transition! (Torq LE > Traktor Scratch PRO)

So I've learned to mix on an M-Audio XSessions Pro running Torq LE. I have officially ordered my VCI-100 (standard) with Traktor Scratch Pro. Now I've heard about all these mods for the VCI-100. Can someone give me a run down of what these are all for and how necessary they really are.

I'm interested in the firmware update, but what does it really do?

I'm interested in the new overlay, but what is the difference?

Is this stuff in stock? Or is the store on this site not up to date?

Will I be able to use my new setup effectively out of the box? Or am I going to really run into some problems out of the gate?

Any advice and suggestions is greatly appreciated. Oh and keep it in Lehman's terms. I'm not up to speed with some of the traktor and vestax jargon...

Thanks in advance!

ErikC