Flying an SEP on an ILS at a relatively busy A/P, the problem is keeping the speed up not down and as Gertrude eludes, keeping the glideslope in check when you eventually do pull back on the speed and drop the flaps.
Encountered more of slow SEP approaches in Florida. Going into Ormand Beach, position approx left base, cleared to land No. 3 with the preceeding pair visible in close formation in front. No surprise that the check ride included focus on maintaining slow flight (obviously with flap) at just above the stall speed (less the buffett) for this very reason. Spent quite abit of time doing that and the need was pressed far more than we see over here.
I can recall a number of occasions in the UK in the pattern at various airfields, where spacing was affected due to an apparent inability to consider and apply lower speeds to that of the 'norm'.