I think the cost of the VK is much more than the cost of the VQ. That might be one of the biggest reason to use the VQ over the VK. VK is more technologically advanced the VQ in term of the material used. I think that's the major reason to use the VQ. If you noticed, all the cars/SUVs w/ the VK engine start their price above $40k. Bumping .5L in a 3.5L engine is only an increase of 15%. That's not that large when comparing with others such as the K-series engine from the RSX/TSX or the EJ-series engine from the Impreza/STi.