Do mr2's need a new ecu or some type of chip when boosting.

what?

No.

Vang, if you are talking about the MKII turbo MR2s ... no, they come with an eCU set up for boost pressure.

If you are talking about the MKI supercharged MR2s, they also have ECUs set up to see boost.

Any other MR2 is going to need some sort of "help" in adjusting for the extra air that an added turbocahrger or supercharger would be supplying.