I think Pfadt's are the only inverted coils that have the one adjustment knob on the bottom of the shock. I think you adj. both front and rear from the bottom.
Pedders & BC are on the top. If you are not planning on adjusting much, there may not be a need for the holes. By jacking up the rear of the car, the wheels will drop and allow you the space to get in and adjust by hand. The holes are not necessary, just make it faster and easier to adjust. There are also rubber gromets that will fill/seal the holes if you go that route. Fronts adjust from the engine compartment.
Pfadt, BC, & Pedders have one adjustment knob that adjusts both rebound & compression.
KW has the V1 with no adjustments and the V3 that you can adjust the rebound & compression separately via the top and bottom of the shocks. All are mono-tube with the exception of the V3's.
Read up on materials that go into the construction of the coilovers, oils used, valving, as well as the testing methods to get the products right. My order of choice right now is: KW V3, Pfadt, BC, Pedders. I think Pfadt's are the most expensive then KW V3, Pedders, & BC are the least. I think BC may be the low hanging fruit when it comes to coils. They were at the top of my list and then I starting thinking again.
Wait 90 days and there will probably be another 3 choices to add into the mix! Eibach, Koni, etc.
KW-Germany.....Pedders-Australia....BC-Tiawan.....Pfadt-US?