Mine is tandem but it's still the same. If you count the radius of the axle tube, add the perch height that is welded to the axle and add the spring pack thickness you will have the number of inches that the trailer while be raised as everything moves from the top to the bottom.
The good: More clearance, more off road capability, personal preference as to how it looks.
The bad: It is more top heavy, the stabilizers may not reach at times, the first step may be too high (getting a new step with one more step may help but sometimes just shortens the rise on all the steps but may still leave the first step a little high.
I dont think I would be afraid of the top heavy, just drive smart. My last old Jayco TT sat low and would drag at the worse spots in some fuel stops etc.
Shocks are no big deal and now is the time as the spring plate holds one end of the shock. They most likely will need welding
I used the Dexter kit and welded the new perch.