I run 215/45 up front with 255/40 rears on custom 17x7/9.5" Fuchs/BBS wheels. Look at the pics in my garage.
I thought the 215/45's up front would be noticeably smaller than the rears and that's the look I wanted but they're really not, they're approx 24.6" overall diameter which is only 0.3" smaller than the OEM diameter. 205/50 is about the same overall diameter as 255/40 so that's why I didn't go with those, plus less tread and more sidewall. 225/45 is too big for a 7" rim IMO, and would be more likely to rub. I'll prolly keep the 215/45's up front forever and go with 265/40's in back next time.
You shouldn't have any trouble finding 215/45, it's a fairly popular size. I'm running Continental Extreme Contact DW because they're cheap, light, and stick to the road surprisingly good:
http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ExtremeContact+DW&partnum=145WR7ECDWXL&vehicleSearch=false&fromCompare1=yes