Loading cars with options overprice many vehicles. I normally buy my cars with fewest options available. All I care is that it has the engine I want and long as it has A/C and heat, power windows & lock, and radio, that's all I care about. I know most people want fully optioned car or close to it. I'm the opposite.
I paid around $22k for my V6 Sienna. Little less for my V8 Tundra. If you option out both vehicles, you can hit close to $40k MSRP each.
Without getting into individual deals, using truecar.com and my zip code in Sacramento.
Base model 2011 sienna i4 is $23,140
Base model 2011 sienna v6 is $24,054
Base model 2011 Mazda5 manual is $15,588
Cheapest 2011 M6 auto is $16,671
Grand touring 2011 M6 auto is $19,999.
I'd say the sienna and oddysey are a class above the M5 when the grand touring is still 15% away from the base sienna. The M5 is an oversized wagon with three rows of seating.
Mazda's never did get the best gas mileage, but they handle pretty well.