Turbo Underboost after installing Air Filter Cone 143bhp

[AudiA4B8]

Hey I'm new to this site, 

I have an Audi A4 B8 2009 2.0 143BHP TDI.

I have this idea to see how much power I can achieve by just changing the turbo for a hybrid turbo and a remap my figures are 143bhp to 220bhp.

I installed a cone yesterday and bypassed the mass air flow sensor due to the fact the filter wouldn't fit, and the car at first was behaving and boosting considerably and driving fine. I made a 35 minute trip back to my city and then stopped for fuel. 

Once I had fuelled up, it stopped boosting and I had to reconnect the stock air filter and mass air flow sensor. At this point I haven't cleared the fault code that I ended up getting about a few hours later saying 

TurboCharger/Supercharger "A" Underboost condition. (P0299). The car was boosting again but then seemed to go into limp mode and flashed glow plug lights at me. I switched engine off and back on and then an hour later I saw that code mentioned above ^ and cleared the code. 

Gave it another boot and the turbo is working again, seems like a bit of turbo lag but its still boosting, but I'm not sure if the lag is due to the fact I had the cone on their previously and could feel the instant power. Since clearing the code it hasn't come back at all, which is a good sign.

 

The other thing I did, was to derestrict the air filter box so that the flap won't open and close, oddly enough fuel consumption doesn't seem too bad with that being done.

I also seem to have a leak on the EGR valve and the car munches oil and It means that I may have to keep topping up every few months. 

So far, I've topped it once since I bought the car in September but I can see it's going down on the car's computer. 

Not sure if its EGR Valve leak or the actual silicone pipe. I was advised that getting a metal performance pipe would be better for power and that I may aswell replace it if the silicone pipe is leaking oil. I'm very unsure of where to get any of these things though. Some help would be greatly appreciated. For now the car will hopefully become a sleeper and if the car isn't beyond repair and I can achieve the numbers I stated above, I will then turn it into an RS4 with front end conversion B8.. 🙂 I have big plans for this car.