If your fuel system is on the way out running a high ethanol content will just speed up the failure. The higher work load required for any part the faster the compnent wear.
HPFPs are a crapshoot and LPFPs are looking to be about a 80-100K mile maintenance item, so if you're really worried about spending the dough to replace items sooner rather than later just stick to low Exx mixes. If you're willing to spend a little $ then run heavey Exx and enjoy the power and engine safety.
"I'm not surprised you get along well with all the other neighbours. If you put fifty children with Down's syndrome in a room there is going to be a lot of hugging." David Thorne