I have an in-cab tuner for my SuperDuty (PowerStroke) and it cost just over 400-ish. So I voted that, it seems like a reasonable price point to me.
SR #265 | "Quia currus certatus, inferius"
13 Focus Ti Sedan w/Handling Pkg, MFT Sony 10 NAV, Leather
13 Focus SE HB Sterling Grey, 201A, Leather
06 F350 6.0L DRW King Ranch, Sunroof, Rhino Bed Liner, 4" MBRP Turbo Back, AirRaid, Edge Chip w/Pyro