Originally Posted by C ///M
You'd be surprised how little modification is needed when it comes to exhaust "dimensions" between 3 series related chassis. Do you have specific experience here or are you just assuming fabrication will be necessary? Don't get me wrong, I've been doing this kind of thing for a long time, and sometimes certain parts just aren't going to cut it and you're better off going completely custom, but again, there is a quite a bit of "play" when working with complete exhaust systems due to motor movement.
In my case, it's going to cost a lot more to have a shop knock out custom downpipes than either modifying other N54 downpipes or just taking some heat to them depending how far off they are to the connecting pipes. Anyway, I have a buddy who is completely able to fabricate downpipes of any way, shape, or form, but I don't really want to bother him with this. I guess we'll just see how it goes.
I'll report back this winter, I was just hoping someone here would be able to go into detail with regard to the differences between the standard and x-drive downpipes and specifically the reason for the differences (ie: transfer case protrudes out in this location limiting ******* etc...
You are right, there are major similarities on the x3 and 3 series. I do not have specific experience with this swap so there is a possibility that these dp's would fit no problem. Do you have a set of stock pipes to set down there to see fitment? That would be the way to go before ordering aftermarket pipes or fabbing your own.
But yes, I am just assuming that you won't be able to just bolt the dp's on with a perfect fit.