The original balancer on my 340 is pretty much toast as far as the rubber goes so it will be replaced soon. The options range from $90-$120 for a copy of the original cast iron type, ~$180-250 for a steel unit that uses the same rubber system and has a SFI stamp, then you get into the $350 ones that advertise "special" damping rings or the fluid filled type. My original question was pointed at the latter two. It's a street car and won't be drag racing but want to do some road course stuff. I don't plan on spinning it much more than 6000-6500 rpm and it will be limited to 5k until I have an opportunity to freshen the lower end. I like to buy once, cry once so if there is a advantage to the expensive ones over the mid-range, I'll do it. I've searched but really haven't seen any supporting data that points to when you need to go top of the line like ATI, TCI, or Fluidamper. That probably means that one of the decent middle of the road ones would suffice. Some of the expensive ones also pose pulley spacing problems that I'd like to avoid.