The best replacement for s8 is s63.

The best alternatives to s8 are rated as following:
★★★★★  s63
★★★★★  a8
★★★★★  m5
★★★  w12
★★★  r8
★★★  s6
★★  rs7
★★  bmw m5
★★  b7
★★  s65
★  a8 w12
★  s7
★  mercedes s63
★  s63 amg
★  panamera turbo
★  alpina
★  s10 trucks
★  s55
★  bmw alpina b7
★  porsche panamera
★  b&w 803s
★  audi w12
  rs6
  revel f52
  maserati quattroporte
  bmw 750
  r8 fifth gear
  mercedes s550

Your alternative for s8 is not listed? Suggest!
Speaking about s8, one probably shouldn't forget about a2.

Other search terms related to s8 and their ratings are:
★★★★★ a2
★★★★ a5
★★★ audioengine a2+
You have in mind a companion for s8 and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of s8 in all years. Click on graph for more.
s8
s63
a8