tekkie said:
there is really only one other way, remove the stock oil pressure gauge, install a 1/8 npt tee, the male end installs into the block, then on the 2 female ends you can install the stock and the aftermarket one
of course thats if yours is 1/8npt, I know the defi one is, I just ordered the tee last night from summitracing so I can post pics late this week once I get it
well, FWIW the block is BSPT. I guess if you managed to use NPT for it, with no leaks, it doesn't really make a difference, but i had to go BSPT with mine.
Whether or not you decide to keep the dummy light will make a difference in how hard this is. If you don't keep it, you *could* theoretically just get the BSPT to NPT adapter and screw the aftermarket sender straight into that.... yes, it would be more weight than the stock sender, but most likely not so much that it would cause problems. If you do want to keep the stock dummy light as well though, you WILL have to remote mount them (i attatched mine little sender/adapter assembly to the intake manifold support bracket). Theres a thread somewhere where livelyjay puts up part numbers for all the adapters needed for different scenarios, lemme see if i can find it. If you want more info on this method, i'd be glad to help, i've written up several things for different people looking for help.
EDIT: heres that thread...
http://www.msprotege.com/forum/showthread.php?t=123615506&page=2&highlight=oil+pressure
and if it helps heres some pics of my install (i know its kinda hard to figure out whats what, but i'll throw em up in case you're interested.)
heres a general shot of the whole assembly, mounted on the back of the intake manifold support bracket. You can use the location and orientation of the oil filter to help get a rough idea for comparison on your car...
and heres a shot of sorta where the hose is running...
and now for where it taps into the block (pic is sideways, again, use the oil filter to orientate). This is where you'll find your stock switch with the green wire running to it. (you can see the stock switch on the lower right, with the green wire running to it.... )