Sterling Trayle,originally of Sumiko(who was responsibe for the Rel stuff,in the U.S.) was very "against" the use of spikes.He talked me out of using them!
His rational was that since the driver fires downward,the sub requires a "specific" amount of distance from the "bottom" to the floor,for good bass coupling.If you use the spikes,then that geometry is off!...A no,no....Made good sense,the way he described it at the time.
Also,it is rediculous as well,since the sub cannot be moved around much.
You won't have to worry about "that"...since you probably have others lined up to do the work anyway.
You now have all the info you need about the Rel,whether a series II or III.In your room it makes little difference which one is used.