your fuel problem is the sender unit is going bad. eventually it won't work, then you need to buy a new one. very common problems with a few selected honda models.

rsx-s muffler won't sound raspy if you do not have a resonator, if u don't have one, that is why is raspy. i know it sounds sweet with both a rsx-s muffler and a s2k on cars before. nice deep melow tone.