I drive 2003 RX8. Not Type-S
I've got a 16 inch Factory wheel.
Is it a good idea to upgrade them to 18 inch?
Is car will go slower than 16 inches on?
If 18, Should I go for lighter one such as chrome?
Braking wouldn't be a problem?
Help me out!

Wow...?
I'll try and help.

Chrome is heavy!
18 x 8 are also used as factory wheels and yes, you will go slower but you will not notice it.
Braking would not be a problem at all.

get some light weight rims.

Thanks for that.
I don't really know much about car.
I didn't even know chrome was heavy. ha ha
Can you recommend any good 18" light rim?

Is it true that suspensions between RX8 and RX8 Type-S are different?
I heard they are. And Also I heard Brake Disk sizes are different between them, too.
Is this all true?
I'm worrying that when cars are made it is to be made what they are for. and Normal suspension wouldn't handle as much as Type S does. Right??

^I can recommend a light wheel, Enkei's. My 8 had 16"s now has 18"s but they weigh to dam much for the AT to pull. I'm going back to 16 or 17's.

getting a sport pkg is not a bad start at all. u can retrofit the 12.7 front rotor assembly off a touring or gt later. and u'll most likely fuck wit the suspension. so if ur considering coilovers or the like... then what good is the better suspension gonna do if u got the touring or GT?

all u have to do to beat us is ur brakes and suspension. what we have to do is figure out how to drop like...100lbs.

Just do it.. do you plan on going on the drag strip ?