I believe it's an 'Individual 401(k)' (aka Solo 401(k) that allows you to defer income, there by lowering your AGI. It's an option for a one-man business, but the spouse can also get on board.part B: Brian, a lot of the rules have changed since I contracted. At the time, a contractor you can put a good chunk of change in a SEP-IRA (self employment). I don't know what dollars they count, but this could be away to bring it down. Ask an accountant.
A SEP is geared toward a business with employees, and all must receive the same percentage which is paid for by the company, but a SEP will reduce your AGI, taxable income and ultimately lower your federal income tax.