If you do go aftermarket ODs,
don't get a Gear Vendors. I haven't driven one in a manual but if the auto is anything to go by the lag/searching/honing between in/out of OD is ridiculous. Splitting gears is just a rumor and will be the same in the manual as auto - pointless. It would be very hard to drive a manual car with the OD, trust me. Basically impossible. Autos are hard enough and even then they're not perfect shifts, not what you think you're getting anyway. I was expecting seamless NHRA style shifts, nope. So, you'd be paying $2,200 for one extra gear (OD) if you get a GV. That's a lot of fluff for one gear.
Keisler are expensive but most top of the industry products are, like tti etc
I'd either keep it or get what you can for it and save for a Keisler. Didn't Mopar make a A833 OD? I'm sure they did.............