Ibanez SR400eqm Pickup replacements

[McBurnables]

Hi all,
ive got a SR400eqm and am looking for a pickup to replace the current powerspan dual coil pckups currently installed, but i cant find any pickup brands that are the correct sie to match the dimensions
any ideas
the dimensions ive been given by ibanez are
width (across the strings) metric:100.5mm standard:3.597"
length (front to rear) metric:34.3mm standard: 1.3505"
height (edge) metric:22.55mm standard:0.888"
height (center)metric 22.55mm standard: 0.888"

ive never changed pickups before so my second question is does size matter?
like if the pickups are slightly smaller will this make a big difference in sound or looks?

 

[Yahboy]

What make you decide to replace the nice sounding powerspan pup？have try with different string ？

I have sr300e which have powerspan inside, try with stock Daddario EXL, GHS pressure wound , labella LTF4A and end up with TiJF344.
.
I prefer Tap mode, push some bass and treble on onboard preamp.Plug into hartke KB15 with flat eq, I get nice growl tone.
The series and powertap is too much fir my taste.

 

[McBurnables]

What make you decide to replace the nice sounding powerspan pup？have try with different string ？

I have sr300e which have powerspan inside, try with stock Daddario EXL, GHS pressure wound , labella LTF4A and end up with TiJF344.
.
I prefer Tap mode, push some bass and treble on onboard preamp.Plug into hartke KB15 with flat eq, I get nice growl tone.
The series and powertap is too much fir my taste.

ive tried different strings, ive owned the bass for 2 years now and want to swap from the current budget pickups to a more premium brand with a higher output. I am also tempted to swap all the electronics to make it active.