The only person who knows what is going on is Sean. At the end of the day, he is a great tuner and hence why we have him on as a sponsor. He has a great deal of knowledge with these motors and also has a number of supporters. A lot of the people that use him speak greatly of what he does. However, not everyone uses him and anyone that has either built a car or required a major re-tune will tell you that these things take a lot of time.
I can appreciate that it is difficult from your end as you just want your car back. Although it's been 3 weeks since you delivered it to Sean, there has been a few things that have come up in that time.
1) the fuel pump
2) he fell ill for a week
3) Jambo - a massive marketing opportunity for him that probably results in a lot of revenue for his business
4) the ECU
The added difficulty is when you have people who haven't built a car before asking why it hasn't been done yet. You've got a brand new engine which is worth some decent coin along with some very nice go-fast bits, you don't want this rushed and botched.
My 2c, speak to Sean and try and maintain a positive frame of mind. I know that it isn't easy, but that's what you need to do.
Bunta and Colin had theirs tuned there and they were both quite nice and white and 32s and GT-Rs.... Creepy