I have plans of a 3" turboback. My plan was to have ARtech weld the flange just strait on the downpipe, neglecting the angle that Mazda used. I was going to just send a 3" exhaust straight back to the muffler with a series of 2 45* angles to offset the exhaust to get around the diff.

However, I have recently become worried that I won't be able to just send the exhaust strait off the back of the downpipe to the diff. Will this be possible? I am worried that the tranny tunnel may prevent me from just going strait back.

Do I have reason to worry or will I be fine?

EDIT: It's hard to explain. Stock exhaust routing looks like this:

Can I neglect the bend?

 

mine is as straight as it can be.... with a dip around the axles since i made it with 1.6 stubs, not my 1 peice axles

this can be seen here...

 

it will have to be bent, it can't go straight back from downpipe to diff.

 

Yes it can.
both my previous 2.5 and my current 3.0 are straight as arrows

 

+1 3" straight as an arrow. you don't need two 45s to get around the axle, just 1. cut it straight in the middle of the bend so you have two straight pieces with a 22.5* bend on the end and weld back together so it forms an offset. with 3" pipe it will be the perfect offset to clear everything. only thing I had issues with is the seat belt bolt sticking into the tunnel. so I had to shorten it a touch. nbd