I was wondering if it's possible to adjust the 'stiffness' of the front suspension. I'm not a very experienced street rider due to the nature of my 907 (more an avid off-road rider), but she's been running fine for over a month now, I think this is a record in the 12 years I've had it , so I have a question: When I go around long curves at fairly high speeds the front suspension seems to be bouncy or maybe spongy, can this be adjusted out and if so, would I want to stiffen the suspension or vice-versa?

The 1st thing to do for bouncy suspenders would be to make sure the fork oil is in good condition , probly just change it . The 907 has the M1r forks and the left fork controls compression dampening and the right does the rebound ( both forks have different internals so if you do pull em to bits do one at a time so as not to get the bits mixed up). There is a rebound adjuster on the right fork leg . So I would start with the recommended weight and amount of fork oil in each fork . I hear the a set of Progressive fork springs are very good .... havnt tried them myself .
Mostly if you set it to the standard oil / amount it will be pretty close , and , unless your really keen , Id leave it at that and get used to it ....... its not unheard of for a man to fuck about for ages and get nowhere

This is off another site that I happened upon when asking myself the same question..... it is very interesting and worth a read as are the links enclosed - if they still exist that is (it is an old thread). Certainly turned an idle thought into a quest which hopefully one day I will achieve correctly.

http://www.advrider.com/forums/showthread.php?t=286065

Even with oil quantity, and oil weights, there is an order to setting up your suspension correctly. Here is a good link.
http://www.suspensionshop.org/tech_suspension_setup.php
I'm sure you can find many other guides. Needless to say, plan on taking a whole weekend to get it sorted.
Start with the springs, then preload. On the M1-R fork, the preload is set with a spacer in the top of the fork. find an appropriate sized steel tube, get our your hacksaw, do some trials. then go on to the oil.

Start with emptying your forks, and putting in the recommended oil weight and quantity, then decide if its right or not. You can't make any decision until you have a starting point that you know.

Just like jetting on a bike, make only one change at a time, and follow the order.
- Spring Rate
- Sag / Pre-load
- Compression damping
- Rebound damping

Match the front and the back for sag and damping.
When I have taken the time to do all of this on bikes in the past, it has made a phenomenal difference.

Cheers, Phil

Easist an d fastest to try is to put a 3 mm washer on top of the tube in each leg.
Makes quite a difference IMHO.
To be more serious, follow duckinthebay`s advice.