It's all relative. You'll always get use to the power. I've had faster cars in the past and it's a viscous and EXPENSIVE cycle full of compromise and frustration dealing with ill-fitting aftermarket parts and trying to be the fastest on the strip/street. I now could care less if the 2012 Mustang 5.0 next to me at the light would run away from me above 70mph.
Over the years, I've learned:
1) 13 and 14 second cars are MORE than enough for the street and is faster than 99% of the cars of the street.
3) It's plenty of speed to have lots of fun in the auto-x
4) It's power you can use and is point/shoot in nature. You really can't stretch the legs of a 11/12 second car on the street for risk of getting a major ticket.
5) I get much more joy out of improving handling, braking, creature comforts, and styling than I do with power. All out power is short lived and can rarely be used.
6) Having that "sleeper" huge HP car is a dream for many, but in the end it's boring because most of the time it looks just like every other verison of its self and you're the only one that knows it's extremely fast. It's much more enjoyable to drive something that turns heads but may be "slow".