Gentlemen:

My 2 cents work on AC and the retractable step.

The AC System I have is Airflow Systems the one Charlie Kohler recommended.   It has an external scoop which has been fully wind tunnel tested, costs you 4 knots of air speed and makes the cockpit cold enough to hang meat!   Actual air temp out of the vent I have measured at 39 degrees F.

As for the retractable step, I had one on my first IVP and never could get it to retract .... spent 28 hrs of lablr and gave up.   My new IVP does not have a step and I really don't miss it much.

Dave Riggs