Indeed, just got my k3vlar back from warranty (though I did have to pay $64 shipping to get it to memoryc in Ireland!) and I'll hopefully be performing the transplant and upgrade this weekend.
I'll let you know how the upgrade goes!
What upgrade are you performing? Did they send you a newer SSD than what you had before?
In any case, Snow Leopard will be a bit quicker than Lion on your system.