Both the E28 M5 as well as the E34 M5 use paper throttle body gaskets. Note that these two
cars had cylinder heads with an almost identical design to that of the S14, save for the number
of cylinders. These paper gaskets are perfectly
adaptable to the S14 rubber isolator. The E34 M5 paper gasket is about twice as thick and might
be a better choice, but both styles work well. You simply place the paper gaskets between the
S14 rubber isolator and the cylinder head. I prefer to use a light coating of Hylomar on BOTH
sides of the paper gaskets, but other users have different preferences. One thing is for sure:
if you employ the paper gaskets, your rubber isolators will function leak-free for a long time.
If you are really ambitious, it is not difficult to fashion your own paper gaskets to go between
the throttle bodies and the isolators (i.e. on the other side of the isolators). Gasket material
can be had at any V8 speedshop and it's easy to cut. I tried this and it worked quite well.