i doubt if the 8 spiders are any stronger than the 6 spiders.
The 8spiders use aluminum gears, while the HB's use hardened steel gears.
I have seen several UE shafts broken...
all the hb's at my local track shred the gears in their diffs even though they're harden steel, they don't mesh correctly. i'll just do what the nitro guys do and put kyosho gears in.