I've bought a set of the stock NGK ILFR7H spark plugs and wanted to install them today but there is a huge difference in length between the BPERIXE(Not 100% sure about the number)in the car at the moment and the stock agent plugs,

 

There plugs on the left look like they're for an Evo 8 and the NGK ILFR7H are OEM for the Evo 9. Did your car run fine before you removed the shorter ones?

 

Yes,they are for the VIII.I've installed the OEM IX ones and car is fine.I've heard from the previous owner he had VIII plugs in,so confusion sorted.

 

where did you get your ILFR7H plugs???

 

Just goto google shopping and type in the plugs. Sort the prices by "total price" (shipping+part cost) not "base price" (which is just part cost) and then a crapload of shipping added on. Shop around on there, they're not expensive and should be under $50

 

From Mitsubishi.