Clearly this guy is not sure what he is talking about. There is physically no possible way 1st gear can feel slow and 2nd, 3rd and 4th feel fast. EVERY gear lower will accelerate harder given its huge gear torque multplication! 1st barring total traction lost will always pull harder than 2nd, 2nd harder than third.
Than 5th suddenly stops pulling at 7500? Again power is made above that and nothing magic happens at 7500 however I have never been there in 5th.
Those dyno's has a wierd blip in them and makes me wonder if something is not right with the car. Dyno's without logging data is almost useless. what was the timing achieved? A/F ratio? That would be able to tell us if the tune was even helping or if your spark plugs maybe need changing etc.
So you gained 5 hp? Sweet