Try checking your air/fuel ratio as well...u never know..:) By the way BHP 97 is not a bad choice either...i would say almost on par with v power and cheaperBro, gonna need some help here. My car was run around 100-120km/h, sometime i can hear my exhaust got sound like fire comes out like (boop boop). Normally this happen during 3rd and 4th gear. Is it got any problem?