My tuppence-worth comments on the goals listed at the bottom of the
linked page:

Goals:
Raise awareness in the general aviation public of the advantages of
the inline twin configuration to drive new product development with
regulatory relief in the form of:
1) In regards to pilot licensing, petition FAA to count the number of
thrust lines rather than the number of engines. Would allow single
engine pilots to fly in-line twins such as the Cessna 337 with just a
type checkout like any other new aircraft. This being done to reflect
the particular training requied to handle the most serious issue in
tradition twin engine aircraft: yaw moment induced by loss of power on
one side, especially at low airspeeds.


IIRC, inline-twin is a separate category. Just because you're rated
to fly a 337 doesn't mean you can strap on an Apache. The feds
already recognize the distinction.


2) Petition FAA to allow for longer (2x?) intervals between mandatory
service/inspection for aircraft using in-line twin configuration due
to robust operation of inline twin configuration.


Doesn't make sense. The complexity of a system drives the inspection
/ MX schedule. The location of the system's components has little to
do with its complexity.


3) Petition FAA to allow otherwise compliant twin aircraft with a
single line of thrust (but 2 engines) to be part of the new "Sport"
aircraft classification.


Works fer me.

4) And regarding Sport classification, remove top speed limitation,
the stall speed requirement is sufficient; if someone can build a wing
with low speed stall characteristic and high top speed, then we'd all
like to have it.


A wing with those characteristics needs moving parts such as Fowler
flaps and slats. Think 727. That's likely to either be so heavy as
to outweigh the category, or require such exotic materials as to be
unaffordable.