Juddering in first gear, how do i resolve this issue?

Causes for juddering may be: 1) Uneven idle, but on a four cylinder car, you would notice the engine shaking if that were the case. 2) Failing guibo, which is the rubber cushion between the transmission and the driveshaft, but those rarely fail on 318s. That is a common M3 problem. 3) Non-OEM clutch facing that does not engage smoothly. Usually worse when cold or damp. Has your clutch been replaced? 4) Heat damage to the flywheel. This is the worst-case scenario because the flywheel for this car cannot be machined and a new one costs about $1000. If that is the case, I would just put up with it.