The best replacement for k20 is k24.

The best alternatives to k20 are rated as following:
★★★★★  k24
★★★★★  h22
★★★★  b18
★★★★  b20
★★★  b16
★★  f20
★  b18c
★  h2b
★  j32
★  b18c5
★  gsr
★  k40
★  k24 turbo
★  f20c
★  3sgte
★  b20 vtec
  b18c type r
  type r
  4g63
  k7
  b18 turbo
  fa20
  kx
  k200
  sr20
  k30
  k24 head
  h22 swap
  2jz
  ls vtec
  b20v
  b18c1
  k20a
  f22c
  k24 engine

Your alternative for k20 is not listed? Suggest!
Speaking about k20, one probably shouldn't forget about k24.

Other search terms related to k20 and their ratings are:
★★★★★ k24
You have in mind a companion for k20 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of k20 in all years. Click on graph for more.
k20
k24
h22