Narrow lobe separation angles (102, 104, etc) will have a rougher, choppier idle, more overlap, and will have better mid range torque and power. It will have a narrower powerband, and at some point, when the power falls off, it falls off FAST.
A wider lobe separation angle will have a much smoother idle, less overlap, reduced emissions, and will have a wider powerband with a less distinct power peak. Power will not fall off as quickly on the top end. Most stock engines use a wide lobe separation angle, Opel uses 110.5 degrees. I´ve seen the best results with 108 degrees with most cams for street use and road racing, but I´ve had good results with 106 for short-track racing....the torque off the turns was better. Wheelspin off the turns at 55 mph with a welded (spool) rear axle!
Bigger Opel engines, especially fuel injected ones, need a wider lobe separation angle. The injection system can´t tolerate a lot of overlap, so you can add some duration to the cam but widen the lobe separation and still have the injection operate correctly. I´ve had good results with 112 to 114 degrees. The 2.4, for example, already has good torque, so it doesn´t need help here. However, the 2.4 power falls off rapidly by 5000 rpms, so the wide lobe separation helps extend the top end but does not adversely affect the bottom end.
I´ve made mention of this before, but my friend´s 2.5 litre I built has a severely ported head, and a mild hydraulic cam with .465" / .445" lift, and 222 / 218 duration @ .050". It has 112 lobe separation. It idles at 900 rpms smoothly, and pulls hard from off-idle. It continues to pull hard to 7000. It is unlike any stock 2.4 I´ve ever driven, yet is arguably just as driveable as stock. It has lost its *truck engine* feeling.