Ok, I have the radio on my bench.
Here are my first impressions based on appearance alone.
The amp looks like a very well-thought-out design from a layout point of view, with the cabling all going to the amp before heading to the radio. Its very easy to work with compared to RCI chassis with the built-in amp. The supplied power cord is made from high-grade, fine-stranded wire, with a monsterfuse link in-line. Fusing is redundant, as well, with each amp section having its own 30-amp internal fuse. The power connector is a heavy-duty unit, and should handle any current the radio could ever pull.
The amp appears to have some low-pass filtering built into it (surprising), and is housed in a pretty sturdy and RF-tight casing. This casing also will be VERY good in dissipating the heat. I'm not sure yet, but it also appears to have some rudimentary biasing going on. I need to test the radio to say for sure. As for the 2879 conversion, just from a first glance, I personally don't think it would be worth the bother, even though it looks like the 2879's will juuuust fit. The rest of the radio is a typical Connex 3300/4300/4600 board, so I won't bore anyone with discussions there.....
Here are my opinions base on some quick tests.
The amp does VERY well (as was expected), topping out at around 375-400, even with less than the best power connection (I used some doubled-up #14 speaker cable with alligator clips for quick testing). Audio is nice and strong with good clarity once the AMC is set properly. The amp DOES seem to have some biasing, because it draws about an amp or so with no drive, and with the AM regulator unhooked from the circuit (no voltage to driver/finals).
Over-all, I think its a good radio. Time will tell if its going to hold up in a truck, though.
I'll see about posting some pics later....
Oh, I almost forgot, the amp board is a Ranger EPA400W10B.