"Pistol grip shotgun" is latin for "miss a lot".
I can appreciate (and moderately agree) that having a shorter weapon is nice for hiking, but if you're looking for something that short, you need to invest in a quality folding stock, not ruin your shotgun to a worthless pistol grip. Folding stocks aren't great, but they are LEAPS and bounds ahead of a pistol grip alone. You have to be very careful with folding stocks, as many of them are just as worthless as a pistol grip, since the cheekweld is terrible.
I gotta agree, just leave it alone. A pistol grip stock (full length stock with a pistol grip) is bulkier than a standard stock, so it's actually kinda uncomfortable when you're hauling it around hiking. I do like full stocks with pistol grips for horizontal shooting (deer, turkey, coyotes, etc), but they ARE bulky for portage. Standard stock, and leave well enough alone.