New M50 swap with a few questions

[Flyin90iS]

OK I'm new here an to E30's, but I have spent many hours searching and reading what others have done here.

I have a 90iS with an M50 out of a 94 325iS. I just bought this car from my father in law as he finally agreed to sell it to me :D He finished up the final touches a few weeks ago, but there are a few things he was not able to resolve.

Brakes:
OK you would have to be a gorilla to lock these up on the freeway! On the street they are ok but not great. This swap is using the 320 booster and stock master, so I am going to try adding a vacuum reservoir and different pads before I try a different setup. Any other suggestions?

Econometer:
The reading on this is WAY off! The computer is showing 45mpg!!! I wish this was true but this is not a hybrid. This was accurate prior to the swap and as I understand it there is a coding pin in the back of the guage cluster that controls this. Has anybody else had this problem and if so how did you correct it?

Exhaust:
OK the stock E30 mid pipe was modified to fit and a high flow dual in dual out magnaflow cat was used in place of the stock unit. A Ansa cat back was then installed in place of the stock muffler assembly. This setup sounds like crap!! It is quiet at idle, but from 3K RPM on the rasp unbearable. It sounds like I have a Honda with straight pipes. Now I have been reading what type of setups a lot of others have used, but I still can't decide what I need to do to kill the rasp. I'm first going to try installing two resonators after the cat to see if that would help any. I have also read that an X pipe before the cat may help as well. Am I just wasting my time trying to make this work? Should I just find a used E36 mid pipe and modify that to work? I just want it to have a deep tone with no rasp. What it sounds like now is an insult to BMW and is not the straight 6 sound that I fell in love with.

Any help you guys can give would be much appreciated.

[smonkbmw]

im running the obd2 exhaust manifolds, obd1 midpipes (with cats) and a UUC catback (for e36) and it sounds SICK. no rasp.

from what i understand if you use obd1 mids, call understeer.com and they can custom order a stromung that uses all the stock e30 hangers but bolts up to obd1 pipes. you have to use e36 hangers on anything else.

[Van Westervelt]

im running the obd2 exhaust manifolds, obd1 midpipes (with cats) and a UUC catback (for e36) and it sounds SICK. no rasp.

from what i understand if you use obd1 mids, call understeer.com and they can custom order a stromung that uses all the stock e30 hangers but bolts up to obd1 pipes. you have to use e36 hangers on anything else.

That stromung will bolt onto e30 mids, not e36 though. They might be able to make more custom units for a price however. X pipes will help to eliminate rasp. H pipes will lower the exhaust tone.

[mazur]

Because of the larger injectors, the MPG guage thinks you're using less fuel. There might be a way to calibrate it, but there will be a limit to how much.

E36's can calibrate up to 21.5#. So us with 24#ers could never get an accurate reading.

[Flyin90iS]

Hmmm so am I wasting my time and money trying to make my current setup work? If the cat and cat back were not new I would just trash it and modify an E36 exhaust, but I hate to spend the extra $$ on that if I can make this setup work. So what do you guys think is the best option, modify what I got, or swap in an E36 midpipe?

If I do go the E36 route is is possible to modify the midpipe so that it will accept any E36 cat back systems, or is that just a pipe dream? Lastly are there any model year E36 midpipes that I should stay away from like the pre-Vanos models, or sedans?