Fumes in cabin. Fuel smell in engine bay

[GTIGUYZN]

Hi. I recently bought a g5 gti. It has a k04 and induction with downpipe. Problem is there are exhaust fumes coming into the cabin. It also has an over fuelling type of smell in the engine bay. There is also puffs of smoke emitting from the exhaust on start up as well if i sit in traffic and then pull away. I had the ecu reset this has given me more power however mentioned issues still there. Please assist wit possible solutions...

[GTIGUYZN]

Ps. I have taken it in to check for exhaust leaks and confirmed there isnt a leak

[panic-mechanic]

So instead of just resetting the ecu did they maybe check
Watertemp that it is seen correct
Manifold pressure correct
Fuel rail requested and supplied correct
Lambda sensor reading reasonable.
Is it stock, does it still have a cat?e
Look under the high pressure fuel pump there is a rubber pipe, those perish and leak.