I just tested the two BAC MONO mods in question, back-to-back. Between the two, Beto's is still the better mod to drive overall. It's more responsive, and much better at keeping the line you want, and you can usually turn in later and hit your apexes and exits a little easier. Also, this newer version tends to break loose in the rear too easily when exiting a turn. At Laguna Seca on Slick tires, and everything else at default, I'm over a second faster in Beto's version at 1:24:011.
My opinion (for what it's worth)...
I love the BAC MONO as a concept and real car--it deserves a good mod with good physics. However, I have never enjoyed driving any release or mod of it. GTR2's version wasn't that great, and PC CARS versions, I felt, were worse. The gearing is off, it under steers and feels "lazy" in the front, breaks traction too easily and it tends to "snap" and exhibit unexpected behavior on some turns and braking situations. It's like you approach a turn, turn in when you think you should, and the car often reacts like your only "suggesting" to go that way. You try to correct, and the car breaks loose, and usually goes into an all-wheel drift. Lap time trashed.
Yes, I can keep this under control and get good lap times with it--but it should be more enjoyable and rewarding to do so. Every version so far, even Beto's great-looking version and the other great mods he's released... this just doesn't do it for me. It should be better. It's certainly not an F1 car, or even an F3 for that matter (though it's close), but it's a low-weight single-seater track car. After watching experienced race car drivers take them out on track, driving one gets them right in the gut, and you can tell they feel an adrenaline rush when they push the car. Yes, this is a simulation, but it just feels somewhat "broken" or off as a mod, and not even close to what I would expect from the real car. I think the existing approach to the physics of the mod should be thrown out, and set up again, from the ground up (so to speak).