I own an ep3 hatch and I want to put some new wheels on it and drop it. I was thinking I would put it on some 18'' wheels and drop it on Tein S-Tech springs. According to the Tein website it should drop it about 1.4'' in the front and 1.3'' in the back.

My questions are:

-Do i have to worry about camber issues with a drop like that?
-Can I keep the same overall wheel/tire diameter with 18'' inch wheels?
-If I can't, will I have to worry about rubbing the fenders (after that drop)?

 

You'll have negative camber in the rear, even with a mild drop like that. But, as long as you have the toe angle set to zero, you won't chew up your tires. Front camber will be fine.

You can fit 18's in there. What year is your EP? The 04-05's, I think, came with a 205/55-16 tire size, so the closest size in 18's to stock is 205/40-18. My '02 EP would actually work well with the same size, too, even though its stock size is 195/60-15.

Use this:
http://www.miata.net/garage/tirecalc.html

Get wheels with about a +45 mm offset and you'll be fine. You'll probably be slower with the big 18's, but you shouldn't rub or anything.