Technically just doing the upper is going to give you a lot of strength and should be all you need. But the lower is a good backup and the real cost here is the install cost. I image the welding cost of the lower at the same time as the upper is almost nill.

So bottle line is you don't need the lower.. but for the cost you might as well

 

All good points and If I were going to buy a set of tops and bottoms, I would definitely put them both on. But I was just thinking of fabbing something up for the tops and welding them in myself.

 

I did the lower "C" about a year ago and purchased them from ploy peformance. I do have a 30 dana and just for info. light off roading and 4.75 back space wheels.

 

How much did the welder charge you for all four gussets? thx

 

I paid $550.00 for sleeves and gussets installed, parts and labor.