I would definitely go with the stage 2, regardless of application.
Stage 1 is a good kit, but very limited - especially with the fuel you run. The stage 2 will have a bigger pump capable of more volume and higher pressure along with a more robust controller. It can be tuned in for towing or max hp from stock HP on up to the limits of your truck.
The stage 2 kit does an amazing job of cooling down the EGTs and can give a big kick in HP if the meth is up around 50-60% (actually higher EGT's though). For about $100 more, you'll never be wondering if you should have gone with the stage 2!