Since it's on you, I'd go after Kohler again. Simply start anew. Get a written diagnosis from the second evaluator. Send it to Kohler and start a warranty claim. Pretend it's the first time you've called them. 1) Tub was purchased from _____ on ____. 2) Tub was installed on ____ by a licensed plumber in accordance with the manufacturers instructions. 3) Within days of the installation a squeaking noise was heard. 4) You had two people come out and diagnose it as a delamination. Include the written report from the second person. 5) State what you want: A new tub. I'd also contact the point-of-purchase. They sold you a bad tub. As a follow up to the initial phone call claim with them, include the written delamination assessment made by the second evaluator. Send them the same info noted above. Written letters and emails start the paper trail. Phone calls are great to "shake the tree", any time you talk to anyone note the day, time, person you spoke with, case/claim number if they assign you one, and take brief notes of the conversation. Kohler is usually pretty good about claims. Best thing I can offer is to be calm but firm in your conversations, be businesslike. And keep good notes. When I've dealt with things like this, I've kept my notes in a document file on my computer. If I talk to someone new, I'll email them the file while I'm on the phone with them. Depending on the situation I might password protect it or convert it into a pdf file before sending it so it can't be muddled with by the recipient. No, I've never done or had done a gel injection. I've never heard of it being done. Not saying it won't work. But I've never had a tub delaminate! As a bit of a last resort, talk to your GC. If Kohler is claiming the tub was installed incorrectly, that falls back on him and on his plumber. You might be able to get separate letters from the plumber and the GC saying that the tub was installed IAW the manufacturers instructions and that they agree with the evaluation that delamination as a result of a manufacturing defect are the cause of the squeak. Again, all that is based on the tub having been installed correctly. ie, it's not a drop-in tub that is being supported by the rim instead of by the base/feet for example. Again, good luck.

Cast iron retains heat better than acrylic. It would have been my first choice for a remodel, but I couldn't find one that fit our space (alcove 30x60) that was deep - over 12". I ended up going with acrylic - a Kohler Archer. It is nice and deep and I'm perfectly happy with it. The contractors would have put anything in that we specified - that wasn't an issue. I don't think there is a difference in quality between American Standard & Kohler - both are good brands.

I guess I had just been looking at Lowe's and HD to see that a porcelain tub is $255 and acrylic is $250. I figured that was pretty darn cheap and don't see a reason to not go that route. I'll have to look into cast vs regular steel to see what the price difference is. If it's big I'm not sure that I'm willing to spend a big chunk but I'll have to discuss it with my wife.

We had an old cast iron with bad rusting on the overflow drain. instead of replacing it we had Miracle Method refinish it. They repaired the rusted out spot and replaced drains. Our tile was in good space but an ugly yellow so I had them spray the tub surround too. So much easier than retiling, and it looks great. It does stink for a few days but worth it.