best route to go is to fit a frs tall block, people have seen 390bhp from the standard bottom end and no zt oil pump problems

then st170 bottom end with frs 1.8mm headgasket and black top head, with uprated valve springs, good for around 300bhp

silvertop with block bored to 86mm and fitted with c20let pistons and rods modded to suit, and uprated valve springs with frs gaskets and arp rod bolts good for 270bhp, its worth thinking about at this point that its only an extra £250 for steel rods and they come with arp bolts so will then piss 300bhp