I've had 460 miles out of a tank of propane once, (100L tank so it holds 80 litres). Once that runs out just switch over to petrol and run for another 450-500 miles 
Can't be many meegas out there that'll do lands end to john o'groats without stopping for fuel
Not bad for a 3.0, although I don't use any fuel to heat up transmission fluid in mine 
Admittedly those kind of figures are the exception rather than the rule, more often than not it's getting a bit of a caning and shifting up at 6,000 RPM doesn't get those kinds of economy figures lol.
I find manuals heat up nicely - thats when gear changes ease off
I will name a manual you would hate!
Escrote/Orion - the version before the Abysmal, due to bad gear change I killed one.
Change was
.1.3.5
2.4
Kept doing 1-4 rather than 2 - next pool car was an Astravan
LOL yeah some of them are terrible, but you know if they made a slushbox version it'd take a week to get to 60 MPH and shortly afterwards the box would disintegrate 
I remember driving an Escrote van ages ago with a really dodgy clutch release, it would grind like a bugger trying to get into gear! So the solution was to put it in 1st with the engine off, start with the clutch down, drive off, then carefully match all the shifts to the driving speed
Proper shed this thing, I'd have even considered swapping it for an automatic it was that bad... well maybe not quite THAT bad 
There are a lot of poor gearboxes out there, for change quality the best I think were the 1970s RWD boxes, the change on my old Sunbeam was superb, box not very strong but very quick and accurate, Mk2 Escort was pretty good too!
It all started to go wrong with FWD and heavily sprung gear levers.
A few years ago I would have poo pooed and auto, but driving conditions have changed so much, and to be honest the GM auto is a better auto than the manual is as a manual if you get what I mean.
I have driven Granada autos - not as good as GM.
Ones I have driven
Worst manual was the escrote box, best Sunbeam.
Worst auto Cavalier 3 speed 1600, best AR35