So far I've only found two tuners:

Mine's VX-ROM

IMPUL HI-POWER CONTROL UNIT

The Impul unit looks like some kind of piggy-back piece but it has a trade-in price so I'm guessing that means you have to ship out the computer. Same with the Mine's unit.

I wouldn't do it just yet cause there hasn't been any word yet on any good ones with good reviews, plus I haven't seen other members talk about one just yet, how credible are they?

This is the detail page for the MINE ECU...->

VX-ROM for INFINITI G37COUPE !Products Info.VX-ROM for INFINITI G37COUPE MT is finally on sale!

Its specs are as follows:

・Changed the data of electronic throttle ・Changed CVTC ・Changed eVTC ・Changed the Speed Limiter Control ・Changed the Rev Limiter Control ・Changed the fuel map ・Changed the ignition timing map (High-octane map/Regular map) ・Upgraded the fuel economy and response.

For alterations, please visit our store or send us your vehicle's computer as we will tune it up without changing the immobilizer function.

　Price：　96,000 yen 　※Complete setting is not available to buy.

For inquiries about this product, please contact us.

Here's the link :http://minesoverseas.blog100.f...=vq37

Not sure whether it would work for a US car.. it would be fun to try it and dyno the difference... cost in US $ is $935

The Impul unit seems like it will be a good ECU. They're an awesome company and one of the best in JDM land with these vehicles.

I've found toying with the ECU on any NA engine is worthless. Just my opinion.

OBDII has certainly reduced the potential gains, but there is still a lot to be had if properly tuned. The biggest difference will most likely be in throttle response by reworking the drive-by-wire electronic system.

But the OBDI 90-95 Q45s have seen upwards of thirty horsepower unlocked and the rev limiter changed with the NICO or JWT ECUs.