"My understanding is that this should give some moderate power gains as well, but perhaps not as much as re-doing the entire system."

>>>*Improving exhaust system performance doesn't really gain power, it can free up what is wasted power. The OEM's must sacrifice usable power in exchange for smoothness, good early RPM throttle response, and quietness. Their main goal is to sell you a vehicle that pleases you.

I often feel that manufacturers invest more money on those three goals than they do in any other area, except perhaps appearence.

Typically an improved system will result in small economy gains, and more power available to the driving wheels. The gains aren't huge by themselves so unless the system needs repair I wouldn't advise spending the money on a basically all stock vehicle.

Once other engine modifications come into play, exhaust flow improvements then become almost a requirement to take full advantage.

Freeing up a few additional ponies to the ground doesn't sound like much, but remember even 1 h/p is all net, the power sapped by friction and loading doesn't really change.

*Well, the guys with the 37" tires that are a foot and a half wide know all about adding load...*LOL**..at that point, think gears, but even gears will never return the situation to equal. Large tires/wheels are mass, mass is load and wind resistance. Leverage (gearing) recovers some that is lost but never all.

I have always felt that the best money spent is in the exhaust system if performance/economy is the goal. The engine works best for all around with a little back-pressure at the port, once past that point the goal is to get the gasses out of there, nothing else can be gained.

The heat is then just waste. Too big is just that, too big, velocity is lost, it can be regained at higher RPM but low end suffers.. Too small is nice velocity but quickly becomes a restriction as speed(RPM) increases.

As with everything, the key is balance........*EB