CTGP-R next to unmodified game?

Hello,

I don't know where I should post this, so I will ask it here, if it's in the wrong place please move it.
I want to play CTGP-R, but I want to keep my game (save) unmodified is this possible? I hope it is, else I can't play it.

Thanks in advance.

Yours sincerely,
Procyon.