Check turbo hoses for splits, 99% be this is a whoosh you heard.... inspect top and bottom hose carefully...
See veloce or autolusso for silicone replacements about £70 each.
2nd, if you've never done it look up mscf thread on here and look at link/details on how to clean egr and map sensor this cold easy cause power issues, when changing gear or drop clutch and back on does power sometimes settle?. All black soot due to hose split will have blocked egr and probably clogged up map (these will cause car to loose power and drop into limp mode etc - likely running issues your seeing now)
3rd check small bore hoses to vgt solenoid (top rear of rad) and replace with 3mm silicone (Few £) follow hose down to turbo and clean the arm on turbo vgt actuator then lubricate.
The hoses will be big issue then maybe egr / map (especially with the clouds of black smoke). Plenty of guides on here and very easy DIY jobs. After all that (do in order over a few weeks). Apart from hoses all free of costs. Once finished it will run like new.
If cleaning egr consider restrictor gaskets (rectangle one with 4 holes and diamond shape with 3) helps prevent egr clogging up again and should cost about £6.
Hope that helps
Last edited by mr-mac; 06-08-13 at 23:13.