Ha ha, yes "swirl-pot" wrote that too quickly!! Anyway, I believe the fuel pick-up is on the right-hand side of the tank/s so when the car goes around a long right-hander the fuel all sloshes to the left and you get starvation until the car straightens itself. The spare wheel-well in a 172 is a nice tidy place to put the swirl-pot and bits. You will use the standard pump in the main tank to feed the SP, then an auxiliary pump to feed a fuel pressure regulator which will send the correct pressure of fuel to the fuel-rail and send the extra pressure back to the main tank. I think the 172 regulator is built into the standard fuel-rail and can be used but it would mean two fuel lines - one to the rail/regulator and then one back to the main tank. Its better/safer/easier to have the regulator near the swirl-pot and main tank, i.e. in the wheel-well and then run just the one line to the fuel-rail. Hope that made sense. If you are considering this then its also worth building a fire-wall over the wheel-well - you would need to do this if you were racing the car anyway.