I was looking for diverters a few months ago and settled on Turbosmart Kompact plumb backs. These are recirculating only though.
Cheapest I could find on ebay was $430 for the pumb backs. The dual port ones (blowoff+recirculate adjustable) were around $500. With our crappy dollar I couldn't find anything cheaper.
http://www.ebay.com.au/itm/New-Genui...Ajm792LJRLFztQ
http://www.ebay.com.au/itm/TURBOSMAR...oSEQGBijJpnBAg
I have actually run the plumb back diverters as blow off valves. Spent $4 on 1" chair leg caps and blocked off the inlets. Removed the recirc hoses and just ran the diverters to atmosphere. Actually sounded pretty good, had it on for around 2 weeks and all my passengers loved the sound. The flanges for the silicone pipes are actually removable and you can replace it with a trumpet from Turbosmart if you wanted to. Have reverted back to recirc now though, just wanted to try it out temporarily.
Personally I don't think I would like to run a BOV on my car all the time, the intake charge air is quite oily (its the reason why we need to walnut blast our cars). After running the BOV mod for 2 weeks I was already getting an oily buildup on the outlet