We're running a Sequence 5800 from our sump. 1/3 of that goes up to the main (dual overflow 120), 1/3 into the stock tank (150g) and then the extra flow goes back into the sump (100g). We ran Schedule 40 PVC
up to the tank and back again. We used 1.5" up and 2" coming back down.
One of the other guys in our club has his piped with flex but when he feeds his tank his tank overflows if he doesn't shut off the flow (I totally don't understand the mechanics of that, but it is what he says, lol). This probably has nothing to do with using flex, but more probably the size of the piping that he chose to use.
Another guy in the club is using a Sequence 3200 to get to his tank from his basement. I'm not sure how you calculated 8' of head... I'm figuring with 4' to the tank from the floor and at LEAST 8' from the floor of the basement to the tank that would be at the very least 12' (probably more as most garage space is larger than your standard 8' ceilings). With elbows, Ts and other bends you're probably looking at around 16-18' of head pressure (there are lots of cool head pressure calculators around). A lot of pumps shut off altogether around 12' so watch which one you choose if you decide to go that route.
I've also seen people build a fish "Room" in their garage with drywall walls to keep the garage odors out of the tank.