Where did you get the automotive cells?
That site is pretty hit or miss with stock since it is all repurposed equipment, but if you happen to catch the right equipment going by you can get a really good deal for anything DIY.
I was about to order a pallet of new lithium cells from one of the US resellers when the batch of repurposed automotive cells popped up. When I was pricing them out I could get the cells and a DIY BMS for around half the price as rack batteries often used by DIYers today. There's more work involved in putting the cells together yourself, but it is nice knowing how it works and how to fix it should a cell fail.