I remember the 9.5 car that was guaranteed to go two tenths faster and it took a year before it went any faster...tuned by the best. I also remember all the 11-12 second cars that never went faster as well. there is a difference between marketing and measured performance. People seem to refuse to learn from history.
The funny thing is that we often have someone tell us that you can sell your old stuff and basically pay for the new, but, they never mention the cost of professional tuning and dyno time that comes afterward...we be preaching to the choir! LOL There is always someone that thinks it will solve his problems and give him the performance he thinks he should have.