Chipcentric in Al Quoz are the ones to go to. Speak to Murat. He's a pro and he knows what he is doing and can advise what will work for your car. He's a real car guy too, has a Delta Integrale. I have been to their garage a few times and it is well set up. They are one of the few that have a dyno so they can actually set your car up properly rather than just guessing parameters and hoping for the best.
When it comes to something like this, quality is more important than cost. It's better to pay for a proper job than to end up with smooth engine bores and a sump full of petrol which will eventually necessitate a full rebuild.