Suspension Setup Question

[K8Boosted]

http://i245.photobucket.com/albums/gg74/zjz125/mx3bigpicture-1.jpg
First off i am not to concerned about the handleing of the car stock handling perfomance is fine for me,, since i just go to shows and fly down a strip once and awhile,,

I am looking into messing with my suspension a bit.. As you can see from the pic above the front on the car on stock suspension is as low as it can go with not having huge problems with driveways, parking lots etc,,, The pic above is 17's with 40's but i am going to 18's with 40's,, but the rear is too high on stock,,,
I am planning on purchasing new struts,,, Kyb Gr-2s
But just using lowering springs on the rear
So stock Height on the Front
And lowering sprigs on the rear
What do you guys think ?
Im thinking maybe this will mess up the thrust line,, I am a service advisor at a ford dealership so an alighment is no big deal