Not recommended. If more then 3" you need more to modify (drive shafts, control arms, etc. etc). With OME lift is closer to 3" then 2". At least on most installations. Next Lift is Superlift 4" (price). When compared you will see what is included in superlift 4". Imagine if go higher.
I dont know this for fact so please if I am wrong let me know. But at least from what I understand, the front the superlift drops the differential assembly some, in essence dividing the change in geometry due to lift between the front drive shaft and cv joints... adding spacers to the ome lift would be 100% of the lift taken in the cv joints, which wont ad up to longevity or durability of the cv joints.
On the rear other than shock travel you would probably be just fine (still alot of angle to add into the driveshaft)...
I have done this and it is not possible, you will damage many upper and lower ball joints, cv axles, rack and pinion, LCA bushings, and limit turning speed. If you want more height, do what i did.. get yourself a Superlift.