I noticed what appears to be adjustment notches on the lower part of the rear shocks and I was wondering how can I raise the suspension? It looks as though you turn it, similar to a motocross rear mono shock.

 

You can adjust it with a "Spanner" wrench. it won't raise it, but you can adjust how stiff it is, and thus how much you sag & drag in corners.

You can find the spanner wrench at a dealer or on e-bay for around $10

 

you are correct, to raise the ride get longer shocks, they will give a better ride due to added travel of longer springs, my 12.5 418 progressive shocks are for sale cheap