I fully expected to make a spacer for mine. I was surprised and pleased to discover that it wasn't necessary. One less thing to hassle with.
I did have to re-make the top plate for the FAB (the oval plate that bolts to the bottom of the fuel servo). Due to the inlet on the bottom of the oil pan being shifted to the pilot's side, it needed to be offset to keep the airbox from hitting the bottom cowl.
Since I was re-making it anyway, I made it from 1/16" 4130 chrome-moly steel instead. The real culprit that leads to top plates failing is most likely the intake pulses, rather than being slammed at startup and/or shutdown. The broken examples I've seen look like diaphragm failures. Consider that at 2500 rpm (semi-arbitrary but easy math) there are 5000 pulses (cycles) per minute, that means 30 million cycles per 100 hours of flight time. That's well into the zone of fatigue life for aluminum, at least potentially. Whereas hitting the side of the cowl happens maybe a few hundred times in the same period, and would result in something looking like a bending failure.
Interestingly I messed up the tennis-racket-shaped aluminum flange on the FAB. When I ordered a replacement from Van's, the guy that took my order questioned whether I got the part number correct. I told him I did, to which he replied that they didn't sell many of those, but they sold lots of the top plate. Obviously a common issue.