You can upgrade the standard power supply in the SG41J1 (250w), SH55J2 (300w) and the SH67H3 (300W) models to the 500 watt PC63J PSU.
This gives the option of putting higher end graphics cards in these models without worry of power shortage.
You can use the Shuttle PSU Calculator to determine if a 500W PSU is needed.
You can purchase the PC63J PSU for $99.99 at Cinlor Tech’s PC Shop.