[Dan Evans]

Is it hard on the engine?

[Doctor Stochastic]

It's better on the engine because the higher effective octane gives fewer knocks and pings. Of course, if one lives in the mountains, you can't get the engine to knock anyway.

In terms of power, the headers were the most effective. (Mine weren't noisy.) I did put a dragstrip shifter on too (the automatic shifted much more quickly than stock), these didn't hurt either the efficiency or the longivity.