The ONLY reason i would ever use a remapped factory ecu is for rego/engineering purposes. Aftermarket is so much better in everyway. You can get an aftermarket ecu to suit a ca18 from as little as $500 if you shop around and be patient. When you factor in the Nistune and a Z32 AFM + plug, its the same amount of cash to get a full aftermarket job. You then delete the AFM as a restrictor and potential fault in the future.

For a limited budget i would get the Haltech Platinum sprint 500, they are $1000 brand new, would blow most microtechs into the weeds performance wise.. I would be running mine on one but it doesnt have the 2 step/launch control feature so im going with the sport 1000 for around $1600