The plans show an aluminum fuel line running through the firewall via a grommet. My airplane has a bulkhead fitting on the firewall. It adds weigh, expense, two points for leakage, and forces you into fabricating a short line with complex geometry you have to tighten up in two places. It took me ALL DAY to make this line, and to install it I have to crawl under the panel. Which I can only barely do with the seat out and my legs down the tail cone and a temporary plywood platform spanning the spar carry throughs.