The 2 Matchbox transitionals that might be less preferable in superfast vs. regular wheel form

Superfast transitionals are my favorite Matchbox cars.  Period.  End of statement.

The best designs of the golden era of Matchbox...  ...but raised up to modern (and realistic) heights, with silky soft suspensions...  What's not to love...?   When I first took up Matchbox collecting as an adult, I was thrilled to read Dana Johnson's Matchbox price guide and find out that being newer, transitionals were worth less than the older regular wheels....   ...Except until I realized that Dana Johnson was wrong and that traditional demand (high) vs. supply (low) economics dictated that prices for the superfasts were rising...

For the next 20 years of adult collecting, I actively sought out the superfast transitionals, until I finally completed the collection just prior to turning 40 years old.  So, now that you know how much I love transitionals, what's up with this post....?  Are there actually transitionals that are less preferable than the regular wheels versions?

Well, no, *I* still always prefer the transitionals...   ...but there ARE 2 models where the transitional version loses functionality relative to the regular wheels versions, so *YOU* might make a different decision...

The first one is the Foden Concrete truck.  The regular wheels version has a wheel-driven gear to turn the concrete drum when the truck is rolled.  However while the superfast version gaines the superfast wheels, it LOSES the gear.

A side note...:  I find the heavy trucks to be the least appealing of the transitionals.  The regular wheels versions have equivalent size wheels, such that the transitional vs. regular wheel height differential that you get with the cars goes away.  In addition, most of the heavy trucks don't get the silky "superfast" suspension, although they are still tagged as superfast. 

The 2nd model that loses functionality is the model that is widely regarded as the rarest (and hence most expensive) of the superfast transitionals, the Pontiac Grand Prix (GP) sport coupe. 

(Another editorial note...:  Having sought out and found all of the transitionals, I personally think that the Iron Fairy crane, the Fire Pumper and the Land Rover Fire Truck are all potentially rarer than the Grand Prix, although the Grand Prix's muscle-car-driven popularity might drive a higher demand and hence a higher price).

Regardless of its rarity, the Pontiac Grand Prix is a nice model, and I like the purple paint color more than the bright red of the regular wheels.  So what functionality did it lose...?  Well, the regular wheels one has opening doors.  The superfast's are cast shut... 

I've wondered for years why Matchbox chose to cast the doors shut...?  Was it that the suspension got in the way with the spring for the doors?  Is it possible to do a base plate swap, ending up with a red version with opening doors but the superfast suspension?  Are there actually a few legitimate purple cars with opening doors? 

In conclusion, there ARE 2 models that lose functionality in superfast form, giving potential rise to the argument that the regular wheels version is better...  But for me, the choice is clear.  It's always Superfast...!