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Exocet is light, in fact the MX5 donor is around 50% heavier so you have a built in performance boost.
Any tune up kit that fits an MX5 will fit an Exocet.
After market ECU with a set of throttle bodies offers a decent performance boost without stressing the engine. Ram in the air with a charger or turbo and increases can be huge, 250 BHP is common but certainly not the limit. We are lead to believe the MX5 engine was designed for a turbo and therefore the internals fare well despite boost.
Which ever way you go, try it first, get used to how well it handles and performs and then boost if you feel the need.