My 00 civic ex (auto) hits 105mph very quickly and it very slowly climbs to the 120's... one time i hit 122 and my car cut off as you mentioned, the lights became dim and it felt like it surged or maybe had that fuel cut you've mentioned. btw my car isn't ne where near stock, but it's also not boosted, so i'm curious to know if boosting it would push the car to speeds beyond the scope of my gauges. since my car is auto, if i drive in D3... it will hit 115mph quickly but it stops there as it hits the rev limiter for that gear. I really don't get why on D4 which is the 4 gears all together it doesn't hit that 115mph so quickly, it's a big limitation when racing.