In theory it is possible to get 400 at the wheel with intake tune and FULL exhaust, depending on the setup and how aggersive the tune is. You also need to have it dynoed just to give yourself a baseline. From what I have seen different models of dynoes are giveing different numbers, so I would find one you like and have all your dynoes done there just to keep consistent numbers. Also within the first 5000 miles you may see a significant gain in HP just from the motor breaking in between 700 and 1500 miles I saw a 5 hp and 5 tq increase. Im having my car redynoed at 3000 miles and am expecting to see another 5 hp & tq. I have seen a post were they were tuning an 05 and got 22 rwhp by basicaly just leaning it out, a more agressive tune may yeald a fair amount of HP. The Corsa test exhaust ( cat back) put 17 hp to the wheel on a stock 05. So having a full setup and tuning it to match might look quite nice