In my 25 year experience with this engine it doesn't start smoothly when cold, like a gas engine. There may be a marginal glow plug - they last about 100K miles - but remember, its a compression engine and until it runs for about 30 seconds it may have a few misfires.
I don't touch the throttle until the engine fires, then I shift into gear and give it a bit of throttle to drive off.
In very cold weather the engine should be glowed a couple of times. ON, glow, wait 10 seconds, OFF, ON, glow again wait ten seconds and START. M-B suggests flooring the accelerator, others say NO that, the additional fuel quenches the then hot glow plugs. I've never floored it.
The shifts are sometimes a bit snappy, especially when the transmission is cold. Clean transmission fluid and a clean filter may help but "they all (occasionally) do that."
Remember, we're all getting used to cars that have electronically controlled engines and transmissions that shift almost imperceptively (the gas engine's timing is briefly retarded to cut its power prior to an up shift); this c.1980 machinery simply can't achieve 2005 levels of smoothness and lack of noise and vibration. Likewise, the old steering boxes can't match the terseness of rack and pinion systems. That's why new cars are bought - they really are better - and cost a lot more!