The best replacement for headers is manifolds.

The best alternatives to headers are rated as following:
★★★★★  manifolds
★★★★  exhaust manifold
★★  manifold
★★  long tube
★  stock manifolds
★  short tube headers
★  stainless steel
★  long headers
★  no headers
★  intake
★  exhaust
★  long tube headers
★  short tube
★  extractors
★  intake manifold
★  4-1 headers
★  name brand headers
★  shorty headers
★  4-2 1 headers
★  stock exhaust manifold
  catback exhaust
  full length headers
  high flow cats
  long tubes
  mufflers
  longtube headers
  cat back
  american racing headers
  untuned
  full exhaust
  arh
  non tuned
  4-2 1
  4-1
  shorties
  ceramic headers
  full length
  zoomies
  ram horns
  cams
  stock exhaust
  downpipe

Your alternative for headers is not listed? Suggest!
Speaking about headers, one probably shouldn't forget about stock exhaust.

Other search terms related to headers and their ratings are:
★★★★★ stock exhaust
★★★★★ page numbers
★★★ flowmaster
★★★ curl
★★★ egr
★★ catalytic converters
★★ exhaust
★★ gaskets
★ turbo
★ electric cutouts
★ straight pipes
side pipes
supercharger
emissions
You have in mind a companion for headers and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of headers in all years. Click on graph for more.
headers
manifolds
exhaust manifold