I didn't like the ugly way I'd previously hooked up the manifold pressure plumbing, so I had TS Flightlines make me a braided Teflon hose to use instead. No more plastic tubing under the cowling:
The hose goes around behind the engine mount and across the firewall, supported by adel clamps:
It's adel clamp city to get the hose where it needs to go without rubbing on the engine mount or chafing through any wires. You can also just barely see where I used a bolt and a couple washers to plug the hole in the firewall where I'd previously had a bulkhead fitting installed:
The single bolt and pair of adel clamps that hold the hoses here took me an hour to install, due to the lack of access:
If I had it to do over again, I'd either mount the manifold pressure sensor closer to the #3 cylinder, or else pick up the manifold pressure reading from the #4 cylinder on the other side of the engine using a much shorter hose. But this is good enough.