With a new riding season for North America quickly approaching, and the hughe influx of noobs with repeat questions (I was totally one of these guys at one point) I figured some back ground info would help. (I hope this is ok to post here, if not my BAD)
When you ask: "what is best" your going to get different answers each time.
Some things are pretty easy to sort out, say which after market clutch slave to buy.
But others such as tires, or pipes, or windshields are much....much more subjective.
When I bought my 950 I tried to soak up as much info from this forum as possible (and the HOW).
While I cannot guarantee the existence of a single individual who is "mr. 9X0" I can say without hesitation that every question you could possible have about one of these bikes has been answered here.
Every thing I have done to my 950, every problem I have encountered, and every solution have come from this forum. I have found out about recalls and issues through the OC that even dealers in my area didn't know about. I cannot understate the value of this resource to a new 9X0 owner.
My advice would be that you sit down with your list of questions and spend some time reading/ searching this forum. There are 9X0 owners here who have wondered the same things you have. So just search, read, and decide for yourself.
You will discover that questions about Tires, Oil, windshields, heated grips, pipes, suspension, and seats have all been covered in great detail, I can promise you that if you write a post that says something like "what is the best oil for my new 990?" or "how to properly break in this bike?" you will get responses from newer members, but those who have been around will just post a link to an existing thread.
When in doubt, and the built in search engine fails you (it will) you can always use google to search a specific site, just type: site: www.advrider.com
xxxxx and hit enter. replace the x's with your keyword and POW, results.
Incase you didn't know or realize it, the 9X0's are more the same year to year than they are different. And while suspension travel, and engine output have changed (especially with the addition of Fi) the majority of parts on a brand new 990r will work on a older 950 and the other way around. As such most of the solutions to problems, or modifications you want to make will work across the board. So if you find an answer to a question about oil or tires or the like, and the bike in question in the thread is an 04' 950, chances are the solution found in the thread will work for you.
As suggested above, read, ride, enjoy.