cats?

i have no cats on my vehicle whatsoever, ok. when i first fire it up, there is blue-ish/white smoke that comes out of the exhaust. while driving, it always has a little smoke comin out the back, somewhat like when your driving in the cold....ya know. but its warm outside. i wanted to make sure that this is common. and my exhaust will kill ya, man if you have to sit at a red light for too long it gets to ya. would cats fix this? are there any that will solve this for a decent price that are still performance oriented? or should i just leave it alone?

i live in tn and i dont have to get the truck tested. i dont even think ive seen an emmissions station in middle TN except in nashville. thanx for any adivice or help.