Yes, the pistol grip is an evil feature, and you only get one evil feature on the M14 type post-ban rifle. You could loose the flash-hider easy enough with a brake, though I dunno about the threads. I wouldn't want to have to weld the thing on.
Pre-ban is just like an AR. You can throw whatever on it.
The A1 stock adds quite a bit of weight to the gun. There's alot more wood in the butt area itself, and the rest of it is a tad thicker as well. You're looking at a noticable increase in weight over a USGI synthetic. Not like 10lbs or anything, but you'll be able to tell the difference when you just pick it up, let alone carry it.
Originally the M14 went along with the M15, which was a heavy barrelled version for the squad auto role. They dropped the M15 and just put bipods on the M14. After a few years of that, they figured out that wasn't quite right, so they made the M14E2 which had the pistol grip stock, muzzle brake, bipod, etc. It was adopted as the M14A1, and the end result was developing a rifle that filled the role of the rifle they dropped in the first place. The M15 would have been better in this role to begin with as it had a heavier barrel at least. The M14A1 still had a standard weight barrel. Oh well, that's the way the Army does things sometimes.
Given the weight of the M60, it was never god's gift as a SAW. I figured that one out the first time I humped the "pig" (we didn't have M249s back then). It weighed a ton. The M14A1 was probably OK for the role when everyone had M14's (though I think a separate M15 designed for that role would still have been better). When the Army switched to M16A1s, a couple of guys in the squad were issued those cheap stamped clothespin bipods. That was technically your SAWs. The M60 was the Platoon's heavy weapon, two to a platoon. In Vietnam they were often utilized in the SAW role, but as there were only two that meant one per squad, and one squad without. Needless to say, the M60 was not the perfect answer to a squad support weapon(though it did indeed ROCK when you needed it to!).
The major problem with the M14A1 was one of heat. The light barrel heated up quick, the M14 ROF is pretty fast, the barrel isn't exactly "quick-change", and it's a closed bolt design, so there's really no great way to cool it down. Being lighter than the M60 and taking common mags with the rest of the squad was a bonus in those days, but the M14A1 was just a bit too light-tubed for the mission.
Another option may be a BM-59 stock. Some of those had pistol grips and can be modified to fit the M1/M14. Don't know how much work would be involved, but it may be cheaper than the M14A1 route.
I think there are some other pistol grip stocks but they cost about as much as the GI one.
Ross