Air retracts are eaiser to install. Manual retracts require a seperate retract servo and the routing of the rods from the servo to the retract is always time consuming. The other issue is there are really only a few mechanical retracts made that are worth buying. Most of the more inexpensive ones do not last and fall apart after only a few flights. As for the Gold Edition kits, they make retracts that are designed to just drop right in when you are building, however any retract will work, you just may have to adjust the mounting blocks in the wings. I am a Spring Air man myself. I use the heavy duty ones which have the 3/16 inch wire. I beleive that Spring Air now has struts. Hope this helps and good luck, Dave