what speeds and what gear? should be easy to calculate what trans you have to tell them you used (sport or normal) and which final drive you should use (3.625, 3.933 or 4.285)
but the evora has much taller tires so i suspect if they are picky about the RPM versus road speed you won't be able to use the stock E153 gear ratio.
the evora has a stock rear tire that is 800rev/mile and the MR2 uses a 840rev/mile tire.
if you use 3.933 gears you're the following:
95% of the rpm in 1st (so if the evora would be spinning 3000RPM, the MR2 will spin 2850RPM)
104% in 2nd
93% in 3rd
and if the test has the evora in 6th and you put it in 5th you'll be spinning 103%
if you use the 4.285 gears
1st is 104%
2nd is 113%
3rd is 101%
4th is 95%
5th is 99%
6th is 112% to the E153's 5th.
and if you want 3.625 gears in your MR2, just tell them you took a standard evora trans instead:
1st is 88%
2nd is 96%
3rd is 99%
4th is 102%
5th is 103%
6th to the E153's 5th is 128%
so depending on what the speeds are, you could easily mount different tires on there and get to damn near 100% of the evora.
what are the two speeds? do they specify a gear to test in?