i am looking at a b20b right now not a b20z. this is basically a replacement motor for the b18b i have now because of fried rings and valves. i will still have the b18 so i may just keep it and build it while the b20b is in the bay. this is just the cheapest alternative i have right now. i found the motor complete for a little more than $500. that is cheaper than a stock rebuild kit fo rthe b18. i was thinking about just building the b20 but since i get to keep my blown b18 ill probably just build that and use the b20 as the work horse for the time being. i do plan to build one of them most likely the b18 to push about 500-600whp. and i do know that increasing the bore on a b18 to 84-84.5mm will stroke it up to a 2.0l and give a better rod ratio for higher revs. i am just going to have to do a bunch more research before i start the build.