OK, I just bought an RTS SM6. This is my second Spyder so I may have a leg up on you.
It is virgin. I've done a couple of things to it so far. As far as farkles (modifications) go, yes everyone is right, to each their own, and you may or may not want to add this or that.
I think, however more to the point the "really really really ought to do" list is as follows.
1) Get a laser alignment.
2) GET a laser alignment.
3) GET A LASER ALIGNMENT.
That's really all the "must have" list. The rest is dependent on your own tastes. Ride your Spyder like you stole it. Once you have a few thousand miles on it, consider the rest of your list. I've included yours and added a couple of my own, in what I feel the order you might consider them in.
A) I also got a set of BAJA Ron Links installed to replace the plastic OEM ones. Not a necessity, just a reliability issue and peace of mind. You could easily wait until one of your breaks (if ever) before you replace it.
B) I had a Spyderpops bump skid installed. I found my previous Spyder was getting the bottom scratched so I had it installed from the get go.
C) I'd suggest the fog lights. The more light you have on the Spyder the better off you are.
D) I also bought the OEM backrest. I installed the Utopia backrest on my previous Spyder. A backrest is IMHO, invaluable for long distance riding, but you may find it different for you. Try to find someone local who has one and just try it out.
Do you need a communication system at all ? Wireless music and passenger communication into your helmet ?
How about a GPS ? Both of these items are more for long distance riding. I'm really liking my bluetooth system.
Personally, I don't like floorboards with a manual shift, but some people love them You will most likely need a heel/toe shifter if you do.
The analog gages and cargo inserts are nice, but are more bling than anything else. Not really necessary.
How much of a noob are you ? Just new to Spyders, or new to riding ?
There is some minimum gear you should have.
Helmet, gloves, jacket, rain suit.
I may sound like a blow hard (and I am), but you asked.
As always, my free advice comes with a double your money back guarantee.