I don't think 20" will make it to where you have to lower it, depends on the tire.. 22" doesn't really matter what style you go with they usually look fine although it will lift your car a bit more than the 20" so either way you may still consider lowering it. Springs is a good option you can remove them when the lease is up...
What color is your car and what color/finish are you planning on going with for your wheels? The stock 20" from the M sport look very nice IMO you can go that route like the ones with 06+ m's go from 18" to sport 19"... Just something to consider...