If you are doing anything custom... don't expect miracles. Things go wrong. The aftermarket parts you have bolted to your car
have NOT undergone the level of testing and R&D that OEM parts have.
Your modified car is not going to be as reliable as an OEM car... if you want much higher performance than the OEM car provides, it's
going to cost money up front, then more money to work out the initial problems, then more money for maintenance than an OEM car.
Unless you know the person actually doing the work, or the person closely supervising them, has done the exact work you are asking,
and on the exact same model car... don't just think they know exactly what needs to be done or all the potential pitfalls.
If you don't trust that the person or workshop doing the work is capable, then either go in every day and check on the progress, or just
don't give them the car in the first place. A company is only as good as the people working in it... a name means nothing. A once great
company might have none of the original staff or owners that made the company great... and might actually suck. That should only be
a temporary situation, as people will catch on quickly.
No matter where you go, no one cares about your car or your budget like you do... why should they? You are responsible for what
happens to your car and how much it costs. Get time and cost quotes for everything... if the workshop is unwilling to give a quote,
then it's up to you to decide if you trust them to do it in a reasonable amount of time and for a reasonable amount of money... which
is often the same thing... labour is always the biggest expense.