I got the stage 2 coil overs and tubular UCAs, fabtech rear shocks for the 4” lift kit as most lifts are designed to level, also used a 2.25” rear block which sits right in the middle of the travel for those shocks. My coilovers came set at 1.9” lift over factory~. It’s designed to level. I also have the Max tow so I wanted stiffer suspension to retain my 12k towing cap. I would recommend between 1.5” and 2” block if you don’t want the nose to be in the air. the stage one is not as stiff and the shocks in that kit are designed for off-road purpose which makes them a little squishy, I have not used them so I couldn’t tell you for sure just an educated guess. Just remember that those shocks are designed without a block, they say they’re good for up to 2”, so you’re putting them at the top end of the travel which will affect how they absorb “shock”. Doesn’t sound like it should matter but sometimes people overlook that.
As far as speedo goes, compare the new tire size(diameter) to stock, if it’s off by less than 1” I wouldn’t waste your time or money trying to recalibrate the speedo, if it’s over an inch you’ll be off about 5 mph over 55. 35-50 is about 3 mph difference.
Hope this helps, you’ll be happy with that suspension and icons customer service is really good. If you’re still not sure they will be happy to help you make an informed decision.