As I understand it you can use that engine and the tranny from the RB25 but past that I'm not sure to what extent of modification is required. Although from what I've read its not too very much more than that. However I've seen people post it would be 10k in parts, 10k for labor, 20k or 30k for mods... This seems rather rediculious to me given that the engine can be pulled for a few hundred and mabye dropped in for a couple grand, and purchased for a couple grand as well. I know I have a lot more to learn on the subject but the numbers just don't add up. Especially the mod prices which shouldn't be so high given the added of space in the engine bay you'd now have as well as a large availibility of aftermarket parts.