Well I am running the ''mugen'' chipped P28 in my car too, but is your car tuned along with a piggyback fuel controller like the VAFC or anything? cause when before my car was tuned, that ECU was JUNK!!! it was running soo.....lean, i lost soo....much power, but with tuning, all the universal chipped ECU's with a VAFC or something similar, they are all the same, so once it was tuned, i was happy with it, but it needed to be richened up ALOT, but I dont think there will be any difference with both of them in peak hp and trq. being tuned, but i could be wrong