Im looking for a good height to lower my tC. I live in the rockie mountains so there is a lot of snow. I have free public transportation so i wont be driving much during the winter. Im planning on putting 18" wheels on just dont know how low i should go. is 1.7in look good? is 2in to low for where i live? I want the car to look super clean and sharp. Do I need to get new struts? What are all the parts needed to properly lower my car?

 

Where abouts in the rockie mountains to you live?
I'm In denver.

"What are all the parts needed to properly lower my car?" <-- this question is relative to the user. You can just do springs or you can do struts and a whole lot more.

You don't NEED new struts but lowering the car will put more stress on them causing them to go out faster - Just the name of the game.

I suggest progress lowering springs. I've been riding on them through these snowy/Ice'd up winters we get here and haven't had an issue. The drop on these is 1.8 in rear 2.0 in front. Levels the car out so you don't have any kind of rake. Currently running the stock 17"s so I cant comment on the 18"s.

 

The lower you go pass 1.5" mark the more it going to cost you in part, upgrades necessary and damages will be made to your car which I'm really tired of for being too low! I did one stupid thing is that I didn't take my car in for allignment for my Raceland Coilover install, which take out two set of new tires within 14mons. the rear was fine, I max out the oem camber adjustment, got a little camber wear but the tire last 2.5x longer then the front two tires! I had it lowered about 1.8" in the front, just a little camber wear too it's all on allignment issue, camber bolt will help a little too.

I would highly recommend to go with either H&R, Vogland or TRD Spring with TRD Struts, I heard few scion tc owner had to switch out the Tokico Blue after maybe 10k it starts to be really bumpy! I had S-Tech > Raceland, now end up with TRD Spring, saving up for the TRD Struts, for the rear OEM Camber adjustment is still good for the drop, just need camber bolt! so if you go lower you'll be spending another $200 for rear camber kit, front camber bolts $50, allignment $70 and this is gonna be really stiff ride and low which will not work well if you got snow! I would go for H&R Sport, with TRD is a nice drop on 18" but still a little akward cuz front looks little bit higher.

here's a few shot of mine TRD + OEM Struts on 18x7.5 ET35 would be perfectly flush if ET32, might get spacer later for the rear.

 

The first 3 threads pinned to the top of this section will answer all of your questions. Search before making new threads because 9 times out of 10, it's been talked about before.