Seb absolutely does e-tuning with EcuTek. The main programming kit with license and cable is $650 for an off-the-shelf tune on a N/A Z. For an additional $200 you can get a custom N/A tune, for which you will have to do some data logging. There is an extra cost for forced induction tuning. There is even another product option on the website if you already have a license and just want to update or tweak your tune.
Here is a link to the full EcuTek kit:
Specialty Z VQ37VHR EcuTek ProECU Programming Kit - 370Z/G37. See the "Desired Tune" section for the additional options and costs described above.