Dash 4x6's

What is the impedance of the speakers in the dash?   i have a tiny little tweeter in their now and im looking to replace them with 4x6's   
 
i found some Infinity Reference 6412cfp (i think they're last years model) that i think im going to buy. it says 4ohm, is that what i need?
 
 
also, if anybody has any other suggestions on good speakers for the dash, im open to any and all ideas.   im trying to spend less than $70..   i found the infinity's on onlinecarstereo.com for $48 shipped

yep, you need 4 ohm.......the stock tweeter is probably 4 or 8 ohm.