Confused

HI IM little confused today a bought my plugs ,the book servise(nissan) say that the plugs for the primera p11 are bkr6e-y11 ,well I read in the list archives that shorter the plug is ,works better in aurs motors ,so I bought the bkr6e that is shorter than the bkr6e-y11 ,that is why im confused whish one work better in the sr20de?:confused:

after reading that, youre not the only person whos confused :huh: