some cams produce better midrange power while more extreme cams produce power in the high end. the reason has to do with the size of the cam lobes and i know with jun stage 3 cams vs the toda stage 3 cams vs the integra type r cams the toda and jun outperformed the itr cams in the top end but the itr cams made the most mid range power. this is because a more extreme lobe in the mid range will not necessarily make more power. everything is a compromise and the motor will bog in the mid range with an air/fuel mixture that is too rich.

most cams that are stage 2 and stage 3 are designed specifically for race applications where the motor spends all of its time in the higher rpm's. this makes a cam less streetable but more impressive on a dyno sheet and at the track.

just remember, there are always compromises when tuning an engine.

another way to make this point more clear is the alteration of vtec engagement points. if someone you know has a vtec controller and lowers the point of vtec they won't necessarily feel an increase in power, but rather a feel of bogging and sluggishness. this is basically the same thing your customer is talking about with the stage 2 cams and why the stage one makes better mid range power.

overall, i'd suggest selling him the integra type r or civic type r intake cams. they make the best mid range power of any cam that i've seen and this is because honda knows what they're doing. no, they're cams aren't as impressive on the top end but they're much better for daily driving.