mine isnt lowered but when i go up the begging of a steep hill it scratches the bumper a liitle. and when i go down my friends driveway the muffler scrapes against the road. my friends box scion was lowered with airbox shox and when it was at it's lowest it would plow speed bumps so he had to raise it up every time we entered the schools parking lot.
so just think that with lowering it may be dangerous but if u were to get a body kit that would be the worst.
adding body kits, lowering springs,performance chips, ect isnt really for everyday driving, just saying. If i were to do all that crap to my car i would make sure i have a primary car for trips and bad weather use.
dont get me wrong...just lowering springs is fine but just saying the springs wont be best in snow..
as of being able to ajust heigth in different seasons, idk if there is a spring for that, you would have to put a higher spring or stock spring back on in the snow season or u could get air springs but that would cost like a thousand and will probably break once a year with 300 dollar repair...
so just get any size springs in summer and switch back to stock in winter, i would only do that if u or somebody u know can install for free; plus a lot of people do that with rims/tires and switch to the stock all season tires in winter then just switch back in spring