zstorm

Hey guys,
so im a total n00b to the z32, just got one a few months back. 1990 N/A automatic with the t tops and 2+2 seats. Its a bucket that I got for cheap but it needs a solid amount of work. One thing tho, it had some ancient Greddy glasspacks (? not sure if they really are glasspacks but they definately sound like it) that the PO put on it, and I blew one of them driving back to the city on the highway a while back. I know that without a muffler the backpressure on the engine gets messed up but how bad is that for the car exactly? Cause I've been broke (lost job) and haven't been able to fix it (am fixing it soon however) Also, pretty sure it needs new cats as well. Makes a loud rattling sound at idle. Also, the car cuts out / bogs down at idle when fuel level is low. I am fairly certain at this point that it is due to filth/rust in the gas tank which is getting into the engine causing it to seize up... like I was going about 85 mph when it cut out on me one day, and i just fired it up again and it worked... anyways, Ive sorted out most of the issues, but I want to hear what you guys have to say. Like I said, Im a newb to the Z chassis (although not nissan, my previous car was an r50 3.5LE) so maybe there is some insight you guys can provide me? Thanks for listenin'