My first sugestion is to come out to one of our events and see in person what some of our members have done, talk to us to learn the pros and cons of the different mods (and maybee get a test ride.) The 2nd Sunday Ice cream social or the 3rd saturday Pavillions car show are good opertunities for this.
Many of the R56 owners Go with H&R Lowering springs (Model 101-726 is 229.95 @ MossMini.com), They bring the car down about 1.5" and make the car ride really nice.
Some R56 owners will also get the adjustible rear control arms to help with alignment issues that can be caused by lowering (Alta model 102-745 is 239.95 @ MossMini.com) Not a must but make the tires wear a little easier.
Or if you want the ultimate in adjustability you can get a Coilover system like Sushil mentioned, It will allow you to set the ride height whereever you want it as well as change the shock dampening to suit your taste. (H&R model 102-690 is 1064.95 at MossMini.com)
If you like taking the corners fast and want to get rid of some of that body roll then a 22mm rear sway bar is the next step (Alta model 101-912 is 219.95 @ MossMini.com).
The next step beyond that is to get rid of the bricks that they call run flat tires and put some real tires on the car!
All of these parts are fairly easy to install and with the friendly group of people here in the club someone is always wiling to help out (myself included)
BTW, I'm not a Moss Mini freak, and I don't know if they have the best price or not, I just used them as an example.