Did a search but no thread seems to cover this one -

Suspect idler pulley upper left (06 XLTScab 4x4 5.4L) needs replacing - started 'ticking' @ idle, disappears w/ WD-40 sprayed on bearing area. Truck is @ almost 60k miles.

Replace w/ stock? Cheap enough @ under $20. Is billet all show? Have seen a couple of posts on other forums that METCOs wobble, etc. @ triple the price of OEM. Any recommendations for reasonable cost, high quality?

Plan to replace serp belt too. Should I replace any other pulleys since I'm in there?