leesti

i have a v4 sti and i recently noticed that the car has started to hesitate when it gets to around 4000rpm, i have recently fitted a silicone turbo inlet pipe and a large air box hose ( the car seemed to be fine before these were fitted ). and when i started the car this morning it blew blue smoke out the exhaust, (no smoke when driving or when turbo kicks in) just when you leave it stood then start it.
can anyone help????