Hey Rene - can you fix that missing image - I'd like to see what the multi-rib housing looks like.
I just took a look under my 98, I count no less than five ribs - three full length - top bottom & center front, and two shorter ones in between.
Edit - OK - it seems there was a database problem over at Suzuki-forums, preventing the image from displaying.
I have the housing in the second picture, which as far as I know is the original - as a matter of fact - that is my front diff - I can tell from the red anti corrosive paint on the cross member.
Looking at the Suzuki EPC, it seems that the "multi-rib" diff housing shown (27611-67D00) was used on manual transmission 2.0 GVs in 98, along with the later automatic transmission 2.5 GVs and also the automatic transmission turbo diesel engined GVs - maybe you should look for a manual transmission front diff and swap your third member over.