im pretty sure you cant use the (i) head on the eta motor only on the super eta's the eta's have flat pistons and the super etas have a dome shaped piston. so theres clearence issues. also if its a 325(e) and your redline is only 4500rpm its pretty pointless to turbo because your trubo probably wont start spooling untill 3000rpm so that will only be 1500rpm of boost.
so thats my opinion that i would contribute.
im going for the m50 or s50. just have to part it out and find a motor in canada i know the s50's are hard to find with low kms