Many things aren't used for their intended use.. but work fine.
Many have no issues, and many follow the manufacturers guidelines a little too heavily. More to the point, they probably would prefer you to pay the extra for the intake one.
Many people say "yes" and many say "no"... but whatever works works. It worked for me, and seem a few others on the forums here.
But if you feel safer with a GTR or the intended "intank" one, change it for one of those.. i'll help you install, now you know how to do it that is most of the work done.
The issue here i don't think was the pump failed due to being "intank" or not at all anyhow, it was the pickup falling off.
p.s. i'll buy your stock pump in a month or so too