I'm using the Wizard Cooling rad as well. Have logged just over 15k miles on it with zero issues in my LS1 z. Scott Attig [owner of WC] suggested i use rubber grommets to isolate the rad, drilled the rad crossmember holes slightly larger, installed grommets and bolted in rad using stainless bolts with nyloc nuts so I didn't have to torque them too tightly. My z was the model for the radiator he produces. After he made all the measurements [i was able to provide him a 240, 280 & 280zx] the questions he needed answers to were; how many horsepower does this need to cool, what size to the inlet & outlets need to be.
I paid extra for the mounting tabs he tig'd for my LS1 fans to mount and he also made me a tube with nipple on it [to attach the steam tube] that goes between the upper hose section and bead rolled the ends to it seals properly.
I was going to purchase a different radiator [think big name and less expensive] until Scott took some time and detailed for me the differences in his vs. big box or ebay rads. Greatest advantage [other than he's only 90 min. away] is his rad has no epoxy, it's all tig welded.
In the end, I'd go back and purchase from him again in a heartbeat. Great product, excellent customer service, no issues and...a drain petcock!
No, I'm not affiliated with WC, just like what he delivers.