Good then, because I've just had 2 Uniroyal Rainsports XL put on my front (needed 888W rating minimum) and the rears will be the same eventually.
Load Index number is for sidewall flex, XL is for higher tyre pressures.
A car that runs extra loads needs higher tyre pressures to compensate (see your door jam) and an XL tyre is designed to run with these higher pressures.
If you run an XL tyre at low load pressures you achieve Zero, doesn't surprise me the DC5 boys swear by them
Interesting, might explain why when looking at my new tyres, they look like thy aren't quite pumped up, so should probably increase from the standard 30 psi. However, my door jamb recommends 30 for under 140kph (I think) and 34 for above i.e. no relation to weight. Might try 32.