Just saw this thread. For what it is worth this is what I wore for Dakar and training.
Technical underalyer. Will wick moisture and keep you from getting chaffed.
Good pair of socks. Several of them. Do not use cotton. You can wear 2 pair depending on how your boots fit. Put on dry ones each day.
EVS neprene knee pads. People think they will be too hot but they aren't. They are very comfortable with no pressure points and will not slide around. Most comfortable I have ever worn.
EVS or other type of padded riding underpants, full length or shorts. They make them with removeable pads and they can serve as your technical layer.
Koeta Pressure suit. You can't go wrong. Saved my ass.
Jacket, water proof or not? The idea of the jacket for me was a wind barrier. Bring layers with you to put on over the Koerta but under the jacket. You can also add a second thin technical layer under the koerta. For example a technical t shirt under a technical turtle neck. I recomend a long sleeve technical layer. It will breath and keep the jacket and Koerta from giving you a hot spot.
I used the Acerbis Impact jacket and it was damn near perfect. Vents closed in the morning, easy to open them as things warranted. Lots of pockets which is a must. At the start of a stage you are packed up like a chipmunk with full camel bak, your lunch, second road book, or anything else you might need on the day. A heavy jacket will wear you out. Think thin and use it just a wind break. Your other layers will provide the warmth.
A rain poncho is pretty easy to carry with you if it rains. Most likely you'll just gut it out.
Try to keep as much off of you as possible. Let the bike carry it. You will be up and down all day long. Each time you stand up you have to lift that weight.
The bottom line is you dress for the day. That means you will be cold in the morning and prolly a little hot in the afternoon. That's just the way it is.
Put the pants in the boots. Else you will snag all sorts of stuff and yes they will catch on the pegs.
"Dakar must be a race for few people, Dakar is a dream, the dream of the Rose Lake, if everybody finish it, the dream is over" Fabrizio Meoni
A challenge for those who go. A dream for those who stay behind. " Thierry Sabine