I know this is an old thread, but having done through this process, I'm trying to add some info that might save another from going through the same thing as I did. The OP mentions the windshield glass retainers as being different and one of the responses is they are all the same. They are NOT. The ECV windshield uses retainers that are bolted onto the frame with 1/4"x20 bolts and not the smaller screws that the more standard retainers use. It is a different bolt battern, the snorkle bracket to windshield is different. Black Dog Customes in Madison, GA sells the ECV vehicle retainers in a three piece kit and will paint to match if required. We are also installing a slant back on an M998, but we just pulled all the parts off an m1151 that was being scrapped, and we used our forklift to remove and install the top and B pillar as one piece and the sponsons, hatch and C pillars as one unit, and used all the original hardware, so can't add much to this thread. Hard X doors coming this week, so no comments on the soft doors on a slant back, please. And, this is still a work in progress, used the hood off the M1151 and 24 bolt wheels are going on next, we used the high back seats and the windshield from the M1151 as well as the air lift bumper. So, visualy, it should resemble an M1151, but is tagged, titled and registered in GA as a M998. So, Humvee Salad.