I've driven the BFG's in the rain. Albeit at a Driver's School. They hooked up fine, They were used when I got them, but had lots of depth, compared to others I've acquired. It was raining hard enough i could barely see 10 car length's in front of me. Followed an ITS RX-7 around until he lost it. Runnin in the rain was great! IT7, BFG R1's 205/60/13.
As far as only being good for a year? I doubt it. Our GT-1 car had rains that were probably 5 years old, didnt look pretty but they worked. As long as you take care of them, you'll be ok.
Chris
PowerTrip Racing
IT7 #88