the pressure line feeds the hydroboost first and then goes to the rack
there is also a return line from the hydro, i don't see where t-ing both lines into the return would hurt anything.
if you want a remote reservoir, start with a mc that can adapt to a remote reservoir
most oem mc's will not adapt, but lots of aftermarket mc's available with remote reservoirs
i got lucky, didn't think i'd need a remote fill, used the 03 f*rd hydroboost and then added a remote reservoir
i found a factory five forum where they were talking about using the remote reservoir off a nissan quest
the nissan quest has the same size mc fittings as the 03 cobra mc
