well,im on stock 205/50/17 with the stock snowflakes.Can i go down in size like 205/55/16 for winters and buy some steel rims even though im lowered on Tein-H tech springs (1.4 front/0.9rear)?
There are 3 basic things to worry about when changing rim/tire size.
1) width of tire -- in your case 205 and 205 so that's fine.
2) overall diameter of tire. Use http://www.1010tires.com/tiresizecalculator.asp and it will tell you what the difference is. In your case the 16's will be 0.8% smaller. Which in the realm of tires is so small it's fine.
3) will the new rims fit over the brakes. I don't know the 3 well enough to say for sure, but I would think 16's will be fine.
the lowering doesn't really come into affect unless you are going wider but if you are buying steelies for winter you want narrow not wide so there will be no issue being lowered.