Perhaps you should read the posts of knighty in
http://tentenths.com/forum/showthread.php?t=122355. The IES engine is producing around 500 bhp and is within the budget cap. We will know next year if the package is competitive.
BTW according to google "IES designed the Nissan BTCC engine that was dominant in the class from 1997 to 2000, winning the manufacturers title in 1998 & 1999."