After giving some thought to the issue of modifying the fuel rail or not with our stacked setups, here is my conclusion. Based on the experience I had a few weeks ago, when a plastic tie broke and allowed a fuel line to contact the axle collars near the rear diff. and rubbed a small hole in it, and I do mean small. I didn't even see it until the pump was turned on, yet it still dumped about 12 gallons of fuel in about 10 miles. I think the fuel rail is not an issue. With the larger SL55 pump and adjustable regulator, we can flow plenty of fuel. My AFRs have been fine, so getting the right pressure at the rail is a key. As we know, each car may vary a little bit, we have different combos of stacked setups, so some experimentation may be necessary to get good AFRs. Larger injectors may lower the duty cycle and would probably be the best option but not absolutely required, however, I would recommend running some injector cleaner once in a while, to keeps things clean and working efficiently.