pokemon diamond:Battle tower help

[dark_seeker]

ok making a new bt team
my last got to 96 and lost to a quick claw gullotine from gliscor
old team:gengar garchomp cressilia
i really want another star

thinking of suicune as my tank

suicune@leftys
calm(cant change got that nature)
252hp/252def/6sp.def
calm mind
surf
rest
roar/ice beam(please help me chose)

Note:this is not my lead

breloom i thought would do fine as a physical sweeper
or gyrados not sure

if breloom@toxic orb
jolly
252speed/252att/6hp
subsitute
spore
focus punch
seed bomb

for gyra
standard dragon dancer set

not sure for a special sweeper
please help me out