Hate to rain on yer parade here but my mileage varies by 10% tank to tank and 20% season to season. So one tank with a 5% change does not by any stretch indicate a positive result. Tabulator tape is in the same boat as Vortex Generators, very unlikely to give you much more than a slight gain under the best of circumstances. Tabulator tape is used on aircraft sometimes with very different laminar flow characteristics. Their ability to improve flow on a non-laminar flow car bumper/underbody is very suspect.
