I don't really have a problem with them asking for it for the years he was in office. The years before he was in office is what somewhat bothers me. Using subpoena power on a private citizen just doesn't sit well with me. That goes for any politician, not just Trump.
I would generally agree, but the problem is that a president would likely be compromised before taking office. I think you run for President knowing fully well that your entire life is going to be turned upside down. You accept that cost when you decide to run. I’m not sure why financial records should be any different. There should be limitations, I don’t care what trump buys with his checking account for example. But things like credit history and liabilities are something that should be looked at IMO.