i would put a ross, ATI or OEM harmonic balancer on (i got a new OEM one from from CZP). nissan put the harmonic balancer on for a reason.
Personally i'd only go with a Ross or ATI balancer on a high HP car. Low power street car a GFB udp would be fine but if your spending the coin to pump out 600rwhp a little extra for a quality balancer shouldnt be a hard choice.
yeah surprised how fast money goes when building an engine. going the ati unless i can get a ross one cheap.