I did mine with a 350bhp set up so you take your chances some will say you can use them with 500 others will say they did theres with 350! (my car had 76ooo miles on it and was totally standard and box was fine before i 350,ed it). But in your favour is your car will be light so you should be ok for 350/400 id say but its more the torque so need to worry about but im guessing your torque will match your bhp!