GPower I believe is the only tuner out with a SC kit as of yet. It is however expensive as hell, about $25,000 for their basic kit that produces about 530bhp and about $40,000 for one that changes all the internals and produces about 600bhp!!
Serveral other tuners are working with FI such as AA in the United States, it is however unlikely that these kits will produce over 510 to 530 bhp without working the internals of the engine as these machines can take no more that about 0.30 BAR of boost or risk damaging the engine. It is also unlikely that you will find anything reliable out there even when these kits are developed for less than $15,000. I think more around $20 grand.