I second that.
And I feel like adding another couple of inexpensive things that surely improve our lives:
1) Fuel pump
2) PCV valve and PCV breather filter.
I'm telling this because I happened to replace these 4 things together and I obtained a dramatic improvement under many points of view.
The pump was cracked and weak: this gave me gas in oil, gas+oil leaking through the pump's weep hole and spraying all around, poor acceleration, poor MPG and it took forever to start after sitting for a while.
The PCV system, overclogged, contributed in poor crankcase ventilation and lots of oil (more than "normal" blowby) into the air cleaner, which takes us back in topic