The D in the engine code means dual overhead camshaft (DOHC). This is often achieved by fitting an RB25DE or RB26DETT cylinder head and or turbo to a standard RB30E/T block. The RB25DET will not be normally used. Though originally meant for that R32 GT-R and Team A touring car https://rb26dettcompleteengine14689.dgbloggers.com/28618217/the-2-minute-rule-for-new-rb26dett-for-sale