they sound nice but i heard the speed would be off and I heard that it lifts the suspension so would i need lowering springs? or would 17" rims be better? its for my 10th an. crystal white 7 spoke. so nice. suggestions?

 

it wouldnt lift the suspension at all. it may raise the car and alter teh speedometer if the overall diameter is bigger then your stock wheels.. Lowering the car is entirely up to you. It probably would help look better if you do.

Try this,, enter your current tire size, then the desired size tire you may run on 18s, and it will tell you basically how much it would alter the speedometer.
http://www.miata.net/garage/tirecalc.html

There are shops that can correct your speedometer to correct the reading if you change your tire sizing. It may be worth doing if you are concerned, otherwise as long as you keep in mind that your speedo is off a little bit, you should be ok.

 

i have 18s it would change or alter your speddometer if you get the correct diameters still. what ever the width is by 40 by 18..example of mine 225x40x18. doesnt change the whole rolling diameter