Hesitation problem

[rawyatt]

Hey guys, long time since I posted something but got a new suby and its a 1994 bg5. New to the twin turbo game but isn\'t to shabby when VOD isn\'t kicking you in the teeth. Anyway car was running good, then a put an exhaust on which mainly has an sti rear muffler on it, still has factory down pipes. Then soon after a hesitation started where primary turbo and idle is fine but when I get through VOD and floor it, at about 5,500 into secondary turbo, it starts to hiccup or hesitates. If i keep my foot down it will get through it but it feels so rough. As I watch the boost gauge it goes to 14 then it hiccups and falls to around 12 then struggles/bounces to get back to 14. Idk if its a coinsidence with the exhaust but iv searched and shown i should replace sparkplugs, check coils so I will in the next couple of days but I\'m just hoping someone else has had this problem and can help me out. It doesnt affect anyother driving, just only when flooring through second turbo in 3rd 4th and 5th. Also a couple other problems but I\'m sure they wouldn\'t effect this, first is when I turn the key to on, I can hear the fuel pump(walbro) prime and then sometimes a can hear a noise after which sounds like someone trying to get the last of the milkshake out of their cup with a straw. I\'m pretty sure this has something to do with the emissions system so I just have to live with it and that\'s fine. Second is when I\'m half throttling it at around 3,000rpm I get a noise like if you blow over the top of an open bottle. Funny kind of whooping noise but I\'m sure after some searching I found it to be a leaky bov. So I don\'t think they will have any play on the hesitation, and looking foward to your advise, cheers

[rawyatt]

Still happening, realised its only when secondary turbo hits full boost it hesitates