[theraflu]

That’s not a subframe. That’s the unibody chassis aka the frame. Don’t see that on these cars. People seem to stitch weld instead or use a roll cage to stiffen.

 

[theraflu]

Fixed back seats hitting the B pillar is common. I had to mess with mine to get it where I wanted it and still fit. It’s close now but works though I only have a roll bar not a full cage like you. Zaclemore is right, common to mod seat rails, as a matter of fact I’m doing mine at the moment but because they’re too tall. If you’re not running the center console you’ll have even more room to use.

 

[theraflu]

Btw isn’t the Corbeau A4 a reclining seat?… why are you using a two piece seat on a fully caged car, not safe in my opinion.
With that said I like how the rear bars tie into the shock towers, smart.