I"d rather use a pressure gauge ;-) but I'd rather not do it at all if other diagnostic means are available, such as a vacuum gauge on the intake manifold. Run the engine wide open for a short time, the chop the throttle. The vacuum should immediately increase. If it does only slowly, then there is an exhaust restriction.
Drivability tests would also reveal really bad carbon-buildup problems. I did not know the 318Ti's "good" characteristics, so I didn't see its cantankerousness as a trouble sign. Let go the gas while in gear and it would be very choppy at engine braking. Smooth shifts were really hard to do! I felt like a total clunk driving this car; I thought it was me. But after the engine treatment all that bad behavior went away and the engine is drivable and fun.
Drill a hole in the exhaust? Not if I can avoid it and fix the problem some other way! Right?