Hi all,
I am planning on working on some long distance projects with a friend of mine. I've got sonar platinum and he's got x3 producer. I plan to use Google Drive to transfer the projects back and forward so there are many issues to contend with. Obviously we need to use the same plugins and the files will be large hence Google Drive. Now of course I will be able to open my friends files but will he be able to open mine as I have the newer version?

He should be able to open the project you send him as long as you don't use features he doesn't have. Still even if you do it should open. 
 
 

Champion, I'm looking forward to trying it out, I think it's a case of keeping bit simple then I will be working on the final mix.

X3 will open SPlat projects and vice versa, although I imagine X3 will display a warning (that you can ignore) that the project had been saved in a later version.
 
However, keeping two versions of the same project in sync is still a challenge, even if you're both using identical versions. You'll simplify things by appointing one of you as Keeper of the Project. If it's you, then you'd be sending your collaborator full stereo mixes (which can be MP3s for convenience) and he'll be sending you the individual tracks that he creates. Those tracks will either have their effects burned into the bounce so you don't need to even know what they are, or they'll be left raw so you can do what you like with them. Neither of you will have to worry about having the exact same plugins or project routing. You'll add his submissions to the mix and send him back the new 2-bus mix for approval.
 
Even if your partner is a better mixer, and you decide he should do the final mix, you can defer handing off the project until after all tracks have been added. At that point, track effects should already be baked in, while bus effects will be minimal.
 
In any case, I'd suggest doing a very simple project first in order to establish the process before you get fancy.
 
 

Yes it is going to be a challenge, with respect he's less clued up than me so the intention is that he will record his tracks first then I'll add my parts and organise the tracks. I think I will send him a track template to get us started. It will be a labour of love which is about helping my friend understand how to get the mist out of sonar.

Be aware, Noel posted a message recently that Platinum projects with Aux tracks/Patch points cannot be opened in prior versions.

I think you get the idea. Simple projects will open just fine. I still have X3e installed and for some reason that's what opens if I open from a CWP icon in Explorer. 
I don't even notice that this has happened until I get to some point where there was a change between versions.