I would think steel tube would be fine. The stuff I used is just a really hard and durable polymer.
Be careful disassembling the seat. The frame edges are rough and will cut you up nice. Gloves would be a good idea.
The recline lever has a retainer similar to an e clip that must be removed and the side trim has metal clips difficult to remove without damaging. I had to rebend the tabs on mine to get them to hold.
Also be sure to route the airbag wire to the inside of the blocks. I initially routed mine wrong and it pulled tight as a banjo when seat tilted forward. Oh and I disconnected the battery since it is necessary to disconnect the airbag connector. Did not want to set any faults.
It took me almost 2 hours, but I could easily cut that time in half now having done it once. Sent from my iPhone using AutoGuide.com Free App