actually there is a problem getting a 1bar spring
if u buy a 0.7bar spring u can use a boost controller and boost higher
but if u get a 1bar one , ur min boost is gonne be 1bar :)
there comes another problem , if u buy a 0.7bar spring and want to boost 1bar , u better get a good boost controller , either way got pro and cons , but tial 38mm is more than enough