Here's a thread over on myG37 that may be of interest, seems like Swift puts a bit more emphasis on ride comfort and also gets great reviews
http://www.myg37.com/forums/g37-seda...rwd-sedan.html
BTW, Coils aren't too expensive, at least the more basic units, especially if you factor in having to get new shocks for your lowering springs (since stock struts tend to have a shortened life once lowered).
Those springs that I listed shouldn't require camber/toe kits, but that's something that you can't say for sure until you get it aligned. If you live in a big city w/ shops that align lowered vehicles on a regular basis you'll have a better chance finding a place that can get it in spec. Some shops don't deal w/ lowered rides very much and maybe just don't want to do the extra work that they can involve.