The fork tubes may be raised slightly in the upper and lower yokes giving you maybe about 1/4 - 3/8" lowering.
A low profile tire such as size 100/90-18, available from Dunlop as the K591, will lower you another 1/4 - 3/8". I know, the stock Metzeler is also a 100/90-18, but the 591s are just lower.
Shortening the internal fork spring spacers will also work. If you do this, just make sure the front end doesn't settle any more than 2 - 2 1/2" on its suspension from fully extended. Otherwise your forks will "bottom out".
Rear end:
Again, a low profile tire will help, such as a 130/80-17, available from Dunlop as the K591. Net lowering: about 1/2".
A 3/4" shorter shock is available from Progressive Suspension, Hesperia, CA.
Seat:
You could convert your stock seat to the BMW "low seat" version or
Have your stock seat's padding shaved thinner or
Order a custom low seat from Corbin Saddles.
Summary:
Lowering the front and rear end WILL negatively affect cornering clearance.
You'll never notice it unless you are going fast in corners. If you can get close enough to the ground with seat mods, this is the best way to go - NO handling compromised.
Maybe a reasonable combination of all the above may be the way to go for you.
Tip:
You and the bike should take the Motorcycle Safety Foundation's "Experienced RiderCourse" (ERC). Will make you MUCH more confident! See MSF ads in all magazines for 800 number of course nearest you.