yeah, thats your 2 options. push it back and go a bit higher.
or run it low, and forward and deal with the other problems.
the reason for peoples different takes on it is just caused by how far theyre willing to go with reshaping the firewall. its generally considered a pretty big no no with concern to rego. by the time you push it that far back it doesnt need spacers/clears the rack, id say youre also getting to the point where the tunnel has changed shape that much, that it wont be really possible to re fit the heater matrix. if you want to ever legitimately register your car this is going to cause an issue.
also to be considered is when you push the engine that far back and it is sitting a little higher, on a really low car, your new 1pc tailshaft is probably gonna hit the floor as the suspension compresses.