SLES upgrade from SLES 10 SP1/2

[iinfi1]

we have oracle apps and oracle database running on x86_64 and itanium systems respectively

on the x86_64 servers we have sles 10 sp1 running while we have sles 10 sp2 running on the itanium servers.

all servers are connected to san using qlogic HBA drivers. is there a way we can upgrade the OS to the latest SP in SLES 10 (i think SP4)
or upgrade it to SLES 11 (latest SP) without the applications having to be re-installed?

do i have recompile all the HBA drivers when i upgrade the OS?

thanks