I went to the Tire Rack site, and I haven't seen any wheels available for the Celica that look better than the stock alloys. A similar-looking tire which looks like it could also be good in the rain is the Michelin Pilot Sport, but they cost more than the Bridgestones. If it isn't, however, I'd go for the S-03s. I use Blizzaks on my car and they're nothing short of minor miracles in the really deep stuff. And while the Blizzaks SUCK at dry cornering, they are virtually immune to hi-speed hydroplaning.
WRs have stiffer sidewalls, which means a stiffer ride.
When fiddling with tire sizes, it's best to stay within the same tire height. And between you and me, wider tires aren't necessarily better. They add to air drag and roll resistance, they add unsprung weight to the wheels, they stiffen up the ride, and they make the car more sensitive to road imperfections, like truck ruts. They also require more vigilance, since they'll allow you to reach your car's cornering limits quicker, and with less warning. I went to the Tire Rack site, and I haven't seen any wheels available for the Celica that look better than the stock alloys.