p.s. i'm currently running a 12mm bing on my stock e50, if that helps at all.
yea it helps illustrate that you're not trying hard enough.
you want to know what's the best carb for a completely stock e50? a bing 12. maybe you need a new one? maybe you just need to figure out what's wrong with your old one?
that said, i don't much like bings on anything performance, and even less so the knockoff clone bings. I've had good luck with SHA's on mild setups like ported stock and pipe or even milder kitted builds. Some of the clone SHA's like Dakar are quite good, and the arrbeo are OK too but weak. The full on no-name knockoffs from ebay and such however are pretty much straight garbage. You could easily get a genuione dell'o SHA 14:12 off buy/sell here and use it with a SHA intake from treats or 77 if you're sure you wanna ditch the bing.