Mechanically, there’s virtually nothing to separate these two versions of what is essentially the same car. Both have the same power and torque and the transmission is the same CVT. The only real difference that could make the GSR feel a bit frisker than your Exceed is that the former is about 40kg lighter.

Perhaps it’s your perception that is the difference here. The Exceed is the more expensive variant so perhaps it has a little more sound deadening on board. That would help explain the extra mass but could also be making the vehicle sound a little more muted and, therefore, less perky. Don’t rule out the spectre of manufacturing tolerances, either. It’s far less common (and marked) these days, but it remains that some cars are just a bit more powerful than the car that came down the same production line either side of them.

Ultimately, even higher tyre pressures can have an effect on acceleration, but if you can detect these small differences, you are indeed a very sensitive driver.

Intermittent problems like this one can be very annoying as they rarely emerge when a mechanic is looking at them. However, you need to have the Mitsubishi dealership mechanic with you for a test drive as you try to make the problem occur, however long that takes. Perhaps you could video the car's behaviour next time it happens and show the workshop that way.

Common causes for a manual car to refuse to select a gear are usually down to a worn, maladjusted or damaged clutch or a poorly adjusted gear linkage. If there's a horrible graunching noise when this happens, I'd suspect the clutch, if not, it could easily be a simple matter of adjusting the selectors. Either way, this shouldn't amount to rocket science in 2024.

Just be sure not to take no for an answer; if the car has a problem, it's under warranty and it's Mitsubishi's problem, not yours.