I finally got the mikuni flatslides I was talking about a few months ago.
They are 38mm not 40mm.
I couldn't find any 38mm inlet manifolds for the carbs so I used some from a set of 36mm carbs,we heated the manifolds and they pushed straight on,they slide off and on the carbs really well now.

Do any of you know a good product to clean the outside of the carbs?
They have gone really dull.

Would it be better to keep the airbox or do they work well with individual filters?

cheers.

As far as I know flatslides respond very well to pod filters, unless you have serious r&d into a truly sealed and presurized airbox, go with the pod filters, you an throw on some velocity stacksand stick on some APE(www.aperacing.com) filters.
Karl
as far as the outside of the carbs, what about some parts cleaner or wd40

yeah, go for individual filters. if the body of the carbs has gone dull, it's probably the aluminum oxidizing....i guess you could use an aluminum cleaner that will remove the oxidizing, but without a finish on the carbs (like clear anodizing), they'll just oxidize again.

I have a set of 36 mikuni flatslide that I have been running openstacked with no problems. I get the best performance out of this setup. Just remeber to keep them clean.