How to wire this correctly

I'm wanting to add a second set of Alpine type R SPR-17LS's to the front doors of my 02' Chevy Avalanche. I currently have one set already in the doors powered by a Rockford 600.4 which is 75X4 at 4 ohms. I am using the front 2 channels for the front doors and the back to for the type R coax in the rear doors. The question I have can I run the second set of 6.5s on that front channel? On alpines web site it says these speakers are 4 ohm but I don't know if that is 4 ohm each or the 2 together with the crossover produces a 4 ohm load? Can I run the second set in series of how should I wire the second set? I do have another amp that I can add but will have to upgrade the power wire to the battery and would like to not have to do this if I can get around it. Thanks in advance.

Thats 4 ohm each speaker, as long as you dont exceed the output ohm level for the amp you should be ok. What size power wire are you running currently?

Currently I have 4 gauge running to a distrobution block that breaks out 4-8 gauge. Along with that RF 600.4 I have a JL 500/1 and would be adding a RF power 250.2 for around 1100 watts which per this https://www.the12volt.com/info/recwirsz.asp I would need a 2 awg to the battery which I would actually use 0/1 because it's easier to find.

Probably the smart thing to do would be to just put the new amp in, run the 2 sets of type R's in the front off of the 600.4 and the rears off the 250.2 and be done with it? Any other suggestions as to how this can be done. I have also thought about just adding another 6.5 to the front doors with out the tweeter but I think I'll still be in the same situation? Thoughts?

The SPR-17LS are seperates the LP are coax, I want to add another set of seperates to the front doors. I do have a set of LP's in the rear doors already but have no intention in adding another set, they are only rear fill anyway. My intentions are to get more volume out of the system, it sounds great just isn't very loud. I figure by adding another set of speakers and somemore power I can get it loud enough to hear the system without cranking it when I'm on the highway with the windows down. Right now this is just one of the 100 other thoughts I have for this truck so please if you have any suggestions feel free.

Actaully I was wondering about the sensitivity on those, couldn't find it either. You're right after doing alot of work on cost to add the amp with new wire and everything else it might be more cost effective to just find a better speaker. I really like the sound of the alpines they just don't have the volume I'd expected. Bummer, maybe I can just shell out for the Boston pro series I really wanted in the first place. Oh well.

Not sure about using those alpines as coax, hadn't thought about. Thanks for your help.

Probably a LOT.  :)