Thank you, everyone, for your replies. I have conducted more research, as you indicated, and have seen sufficient material that prompts me to doubt the viability of using them. I am not seeking a significant increase in power, and I am beginning to question the potential benefits in light of the considerable number of unfavorable reviews surrounding most tuning companies. I am considering following the advice I previously provided to Graffti on this site, which suggests opting for suspension and brake modifications. This alternative is more cost-effective and eliminates the possibility of engine or gearbox failure. The enjoyment derived from late braking and superior handling is equal to, if not greater than, other sources of amusement.