I have a Quigley and did the shock mount mod. From what I could see, it doesn't impact articulation - so much as restore it. Quigley add a 2" lift block but keep the stock upper shock mount in the same place, so the shock runs nominally 2" extended. This nominally compromise rebound travel, with reduced static sag. Relocating the lower shock mount upwards by 1-1/2" restores the shock back close to its nominal static sag. It shouldn't reduce compression travel but should increase rebound travel (droop).
FWIW we abuse the crap out of ours off-road as well and the shock mount relocation has stood up to it.