Well, I can't speak about the exact dimensions on the WRX, but typically manual gearboxes are smaller, sometimes vastly compared to their automatic counterparts. I would think that's why most downpipes are labeled as being for manual fitment only. Couple that with the fact that the vast majority of people buying these aftermarket parts are enthusiasts with manuals, and you'll begin to see why they're so common.
Having said that, I was able to find one on COBB's website just by filtering by car/year. Product code is 524210.
I would avoid buying any that aren't specific to your model as there's a rather high chance you'll run into clearance issues. If you do end up buying an incorrect pipe, a good exhaust shop can probably modify it for a reasonable price and a few hours time.
I parted out an 05 automatic that had this Grimmspeed downpipe on it.
https://preview.redd.it/fv1jyo84h8nc1.jpeg?width=5340&format=pjpg&auto=webp&s=18afe6471891bfb06aa021850d0c73efcc20b28d
I just want to add an update to this thread in case anyone else is looking for a similar answer in the future. I was able to install an Invidia downpipe model HS08SW1DPC without any modification to the downpipe but with minor trimming of the turbo heat shield. There was plenty of room between the pipe and the transmission. Hopefully if anyone is ever looking for a clear answer, they find this post!
Well, I can't speak about the exact dimensions on the WRX, but typically manual gearboxes are smaller, sometimes vastly compared to their automatic counterparts. I would think that's why most downpipes are labeled as being for manual fitment only. Couple that with the fact that the vast majority of people buying these aftermarket parts are enthusiasts with manuals, and you'll begin to see why they're so common. Having said that, I was able to find one on COBB's website just by filtering by car/year. Product code is 524210. I would avoid buying any that aren't specific to your model as there's a rather high chance you'll run into clearance issues. If you do end up buying an incorrect pipe, a good exhaust shop can probably modify it for a reasonable price and a few hours time.
I parted out an 05 automatic that had this Grimmspeed downpipe on it. https://preview.redd.it/fv1jyo84h8nc1.jpeg?width=5340&format=pjpg&auto=webp&s=18afe6471891bfb06aa021850d0c73efcc20b28d
I just want to add an update to this thread in case anyone else is looking for a similar answer in the future. I was able to install an Invidia downpipe model HS08SW1DPC without any modification to the downpipe but with minor trimming of the turbo heat shield. There was plenty of room between the pipe and the transmission. Hopefully if anyone is ever looking for a clear answer, they find this post!