06 vs 08 mpg?

No. There is no difference in terms of MPG capability. In 2008 the EPA changed their testing procedures and it dropped all hybrids down from the prior EPA estimates. So the EPA estimates for the 2008-2009 Prius are the same for the 2004-2007 Prius. The cars are identical in their capabilities and averages.

 

I dont know about you guys but the EPA numbers seem less than generous to me.
I consistently defeat their rating summer/winter

 

Are you using miles per Imperial gallon or miles per (smaller) US gallon? We don't use Imperial gallons here.

 

Usually I convert back and forth to and from US
sometimes reviews use EPA stats here in Au. but reporting can be a bit sketchy and uneven.
I tend to look at US figures to compare.
this is a great tool for conversions
mileage converter - MetroMPG.com

 

^^^
I use Google as my calculator.

Example, Google for: 46 miles per us gallon in liters per 100 km

 

yeah that works

for the first time ever I got to 4.0L/100Km on my usual 150km weekend jaunt,
a curvy up and downhill trip, mostly at speed 80-100KmPH, with few stops.
I'm no youngster so I still remember when we had Imp MPG figures,
and like to refer to that to scale things against my reality

58.8 US MPG, 70.62 Imp MPG

 

I hear you sidecar, I've noticed exactly the same thing. I think the reason that many of us so easily exceed EPA is that the Prius responds so well "hypermiling" (even mild hypermiling) techniques.

My other car is a Mazda 2 that gets about 6.7 L/100k if I drive it normally. If I hypermile the crap out of it then that only drops to about 6.3 L/100k. So only about a 6% improvement.

With the Prius on the other hand it's more like 4.6 L/100k with normal driving, dropping to about 3.9 or 4.0 L/100k with a bit of hypermiling. So a much larger 15 to 18% improvement here.

 

There are some other fun conversions w/using Google as a calculator like these:
10000 furlongs per fortnight in mph
45 mpg in teaspoons per mile