why not just get a late 90's S4 with the 2.7 twin?? same engine man. the displacement is different because the pistons are domed for less compression, but it is basically a 2.8 with twin turbos. thats how I'd go. the B.S. involved in turbocharging a naturally aspirated engine is endless. fuel management, sensors, custom headers and intakes, etc, etc, etc.