I'll throw in my 2 cents of personal experience between two cams I've ran with a similar LSA but very different intake closing events and overlap. Original cam was a solid flat tappet mid 500's lift, mid 250's duration @ .050, and 107 LSA. The cam was made to "pump up the cylinders" so to speak (over 225 psi cranking pressure). With a Holley 950 HP carb, idle quality didn't seem to be an issue at all. Rebuilt the engine with a mid 600's lift, 266/273 @ .050, and 106 LSA solid roller. This cam was custom ground to bleed off cylinder pressure to get the DCR down to run 91 octane and it cranks 150 psi. When I changed to this cam, the idle quality went to hell. I spent hours and hours drilling and tapping holes in the metering blocks, changing the diameter of the emulsion holes, PVCR's, idle air bleeds, etc etc until it wasn't running extremely fat/lean all the time and idle was tolerable. I've finally got it to where I don't have to double foot the brake and gas at the same time at a stop light (this is my street car after all). Part of that was float level being too high, but that was only an issue when braking hard and fuel coming over the vent tube and flooding it. But anyhow, it does seem to me that after reading what some have stated here and seeing the difference in these two cams, that the intake closing/overlap event probably does have more impact on idle quality than the LSA does.