I used to get people like the OP "racing" me all the time when I had my R34 GTR. I'd just let them overtake because I couldn't be bothered to waste the petrol. Little did I know that like the OP they were probably jumping straight out of the car onto a forum to talk about how they "kept up with a Skyline".
Ive been looking into R34's recently as a possible next car. How long did you have yours? Are there any good places to go to for information on them? Im just after running costs, insurance etc. Sorry for the thread hijack.
OP - youre getting boring now. I dont believe a GTR at full speed would "creep away" from you. It would most likely outhandle and outpace your MX5 if the driver was really trying.