OP,
Either of the quoted compressors will do the job you are asking. I've recently moved and currently my compressor is a 4 gallon ~4 cfm @ 90psi compressor I've had for a number of years. It's actually sufficient though not great for most of my needs. It's never let me down in terms of running my 1/2" impact wrench. There is enough capacity in the tanks to get a wheel off and then it quickly refills before pulling the next tire. When working on cars I've never had a case where I really needed full power for an extended period of time so this has been sufficient. With this smaller compressor I've basically limited tasks to impact wrenches, air guns and tire inflation. Of those the air gun is the most limited by the tank size. My air gun use is intermittent but the small tanks are still too small in this case.
My other compressor is a 20 gallon, belt driven Hausfeld Campbell (or however they spell it). It's a ~5cfm @90. It's sufficient to drive a die grinder for intermittent work. It also has enough tank capacity to deal with my air gun usage.
On one hand, others are right to say get the biggest compressor you can. But sometimes budgets are a real issue. If I lost everything and had to restart I would be realistic about my compressor needs and probably get something like the 8-10 gallon HF (or similar) direct drive, oil lubed models. At just over $100 that sort of compressor would cover most of my needs. I just don't see my self expanding to do things like painting and sandblasting so, even though a 60-80 gallon 5-7hp system plumbed into the garage would be cool, it's just not something I need to get my current work done.
Of the two you are looking at I would suggest the oil lubed model but I'm probably biased in that regard. Perhaps the newest oil-free stuff is just as good. I would also ask what is your budget and do you have 240V power in the garage.