when i was looking what to do and who to do the 159 i spoke to a lot of people and a lot of company's, getting mixed results for most of the company's.
i settled on Gus after a few long chats with him and after everyone i spoke to gave him the thumbs up, when it comes to tuning your car you Have to look at all the angles speak to a Lot of people and decide what you want and if it is with in the parameters of your car...
after my experience with Gus there is only one other company i would use if Gus was unavailable and that's AH Motorsports in London mainly because both Alfa Tune and AH Motorsports have a lot of inter company cooperation, and a lot of their tuning is done as a joint venture. Both company's race Alfas professionally and there for know there market Well. I find the problem with other company's is their maps are generic and they dont really know the niche market of Alfa etc and when it comes to a problem they have trouble sorting it out.
Ive used Ah Motorsports and Alfa tune a Fair few times with uprated engine parts and can say they know what they are doing, will offer you advice and help when needed, and will give you the un-suger coated facts making sure you are well aware of what your getting,