The J-spec ecu is for the KLZE, but you also need the VAF sensor as well. The j-spec ecu and vaf allow you to take full advantage of the higher compression, intake manifold, and larger intake ports of the klze. I purchased both the ecu and vaf on here for around $200. However there is an alternative and that would be to get the probinator chip installed in your ecu. If you don't have a klze you have no need for them though.probably emissions and stuff like that i would imagine not 100% sure tho i think in europe they have more emissions stuff than in japan as well so that could be an issue with performance.
What else have you done? I'm guessing you have a KLDE, correct? If you have absolutely no bolt ons than you have no reason to tweak the ecu. If you have minor bolt ons than you have no real reason to tweak the ecu. In all actuality you cannot tweak the ecu, you can use the JDM ecu with the KLZE with good results if you have done the swap. You can also go stand alone and use MegaSquirt, but it really isn't feasible unless you have done some major engine work or have went F/I. I suggest you work on the bolt ons for now get you intake, catback exhaust, high flow cat or test pipe, and headers. These are you basic bolt ons, if you plan on going turbo don't buy headers untill you get a turbo kit.So there is pretty much nothing I can do to the ECU
Enlighten here stoker100, I haven't heard about this yet. I'm interested in hearing.PM me there are things you can do to the KLDE ECU to improve performance. there is one major change in mind that is easy to do, i do tuning on the side so i can explain what you need to do or help you do it if you like.