i had an XTD which is the same thing on my rb20 in my RHD s13..
i beat the shit out of that clutch for a year and never had a single issue with slipping
i had an isis fuel pump in my rb25 hatch and never had an issue..
and i also used twin isis pumps on the supercharged ls1 race car
i would go with isis..
if anything goes wrong with it im sure ken will take care of it