[Rotary Evolution]

i really don't imagine it is that difficult to swap them. the S5 sender plugs right into the S4 harness at the LR strut tower 4 pin rectangular plug. you just won't have the junction on the top of the tank anymore as the S4 is a solid connection to the strut tower.

i have swapped a few S4 pump housings into S5 tanks as the bulkhead connector style of the S4 pump housing is much more durable than the S5/S6 for high horsepower applications without the need to modify the housing for passthrough connections. you do need to cut and add ring terminals to the S5 fuel level sender and low level sensor and modify the S4 pump housing to lower the pump to the appropriate level though. but that is an afterthought and doesn't apply if you are swapping everything from the S5.