Flywheel hp (or gross hp is what I think your trying to say)is something like 175 in our cars and whp (wheel hp) is 143 (give or take a few). You loose power thru your powertrain which is the reason the flywheel hp is higher then the hp at the wheels (whp) Hope this helps
A Tib does lose about 15% through the drivetrain, which is around 25 HP. I don't like using percentages because they are only accurate when the car is stock, but not everyone realizes that. Now lets say you make that same Tib have 250 HP, it will not lose 15% of it's power because it's making more power. It will still lose 25 HP through the drivetrain, not 15% of 250 HP.