+1 what Melbourne_Tiggy says. Unless you're going to a track chasing times then who is really going to know/care. I do a mix of dyno and GPS timed runs on the road. Nothing is perfect and for those wanting hard "proof" unfortunately you're never going to get it. In the real world there are too many variables to get direct comparison/absolute hard and fast numbers.

The biggest thing for me is to choose your testing method and look to keep as many parameters constant as you can. Run on the same dyno or road in the same conditions and hoipefully the main thing that changes is the mods/tune on your car.

I'm not about chasing a particular time (although bragging rights are good). For me it's similar to Melbourne_Tiggy having an unassuming sleeper and surprising people. It's funny how peoples tune changes from "why are you driving a shopping trolley" to "what the hell is in that thing!!!". Some interesting conversations and usually some new levels of respect usually follows.