The main reason a lot of companies haven't come out with something UNIVERSAL like this is that there are many security obstacles.

Even with the hardware LET and I have we still needed to purchase seperate unlock keys for all the possible combinations of Hardware and software in the Crossfires. Rough cost: $10,000.00. Then you need to add in the tuning software which is 100% different then what is available in the domestic and Japanese markets. Rough Cost: $15,000.00. After all that you still are very limited to what you can do though the OBDII port, especially with a Mercedes car.

I think it can be done, but nowhere near the price of 300-600 for a universal unit.