I understand the conundrum. I chose a 7.62x54R Vepr over the .308 Vepr because 7.62x54R is THE Russian round for long-range work. If I was going to get a Russian rifle, I wanted it in a Russian caliber. The .308 is a more practical round with regards to availability of loadings and quality aftermarket magazines, but I wanted the more genuinely Russian model.
Just think hard about what you plan to do with the pistol when you get it. You may find that the original fits your hand well enough for your purposes. As far as low-light capability enhancement goes, you can put a Lasermax guide rod laser into the original to have that capability. I got permission from my CO to put one into my issued M-9 I had many years ago, and it was dead on. It was awesome when we did night fire. Also, there are accessory rails that clamp very securely to the front of the trigger guard if you really have to have one of those. The armorer installed those on our pistols my very last time being assigned one, too, and it fit like it was built in. I wanted to take it off so that I could use my SERPA holster, though, and it actually took me a few minutes to figure out how to remove it.
The bottom line is that you'll be able to do most of what you want to do with the original as what you might want to do with the X model, with just a few exceptions. That grip will probably be the biggest decision point for you.