^If you're getting 17's and tires with a 50 sidewall (profile needed to keep overall factory diameter - thus accurate speedo/odo), then you don't really need to drop it first. But if you're getting 17's and tires with a 45 sidewall, or 18's+ you'll want to drop the car first. The reason is decreasing the stock diameter of the wheel/tire, or plus-sizing rims and not dropping the car first, looks bad. The bigger the rim, the smaller the sidewall of the tire has to be, and when the wheel gap (gap between the tire and fender) becomes substantially larger than the sidewall, it just looks ghetto.
Btw, I would recommend against summer tires unless you find some for a deal. In general summer tires are more expensive and don't last as long as A/S. Yeah the grip is ridiculous, but it's annoying to have to store an extra set of wheels you can use in fall/winter, not to mention switching them out a couple times a year. Also you'll come to love your new wheels much more than stock, and you'll not be as excited about your car all winter. I had a set of Toyo T1R's (best tire I've ever driven on), and I loved them...but I regret just not getting a great set of A/S's to make things simpler. Anyway, my opinion.
But to answer your question, I would get suspension first, then wheels/tires, then put it all on the car at the same time. Imo, one doesn't look good without the other.
