I only cheated on the lower 1/2 bath with a code compliant AAV.We did all the work ourselves so labor was just the fun of doing it.Cost of materials: Main Bath about $2k, 1/2 baths about $225 each from my spreadsheet.We got most of the materials on sale at Lowes: Good quality fiberglass Bath tub $125 (small chip hidden by tile) the toilets $35/each (both non-stock returns), double vanity $175  (side against wall damaged).All the shower stall & floor porcelain tile 75cents/sq ft from auction, Pex, PVC & fittings $185, all elect $100, 1/2 bath vanities $35 each (slight side damage hidden) Lighting $75, all mirrors $100, shower diverter/faucets $275, exhaust fans $30 each on sale. 

If you decide to stick with steam make sure any exposed piping is adequately insulated with fiberglass - we had a problem with higher-than-average heating costs which we discovered was due to inefficient heat transfer through exposed pipes. 

I don’t know if it’ll damage your shower pan liners or acrylic/fiberglass tubs.

I really prefer the look of a 1-peice fiberglass unit with no seams to collect water and mildew.

What I can tell you is that you would most likely want a fiberglass trawler or the like.