For nitrous... ( NOS is a company.. so does Nitrous Express and ZEX)
always start with lower shot as possible. IF you just want to kick some Mustang ass... 35 shot is plenty...kekekkee...
( and safer .... oh.. I miss the miracle of chemistry )
Most NOS kit is the same... it just come with different JETS size.. ( therefore different shot) You need 2 JETS for adjusting shot... each jets cost you $7 - $9. You can try NOS 5115 or 5123 kit.
Be safe.
peace