Type X programming is for a GT-R with a higher boost. It is designed to work with HKS boost controller. The Highly anticipated Mines VX-ROM for the R35 GTR:
Along with the points above, the VX-ROM is programmed for maximum throttle response and engine power without sacrificing fuel efficiency. All important security programs like the immobilizer and anti-theft system flawlessly conformed to the Thatcham rating system function. Considering the safety margin to the newly developed GR6 dual clutch transmission system, the standard VX-ROM does not change the rev limit. (A change on the rev limit is available as an special request.) The boost limit is also set conservatively at 1.1k to protect the engine. The VX-ROM realizes the best combination of performance and durability for exhaust tuning. There is a pair of No1 & No2 catalyzers (catalytic converters) in the R35 GTR (total four catalyzers). Mines recommends changing both exhausts and the No2 catalyzers. However, due to the fluctuation of boost, the No1 catalyzers is not recommended to be changed. Expected gain (U.S model for 92 octane gas + octane booster) VX-ROM alone +10hp VX-ROM + Mines exhaust & catalyzer +50hp Please not, the original ECU has to be sent to Mines Japan for reprogramming.