No I would simply treat it with respect in the wet like I did when driving my nova with MORE than 500bhp and an all up weight of 1060kg and the same mid engined layout!
http://www.youtube.com/watch?v=4S8O-Eoaprw
Some of the people in this thread have clearly never driven a quick car if they think its got to be so terrifying, just cause a car is capable of making 500bhp doesnt mean that you have to use it even if driving in the wet or snow etc, its just nice to have the choice to use it when you want to.
Depends what you are used to, compared to my nova for example a car with only 400bhp and weighing 300kg more is going to feel quite slow for example, but that said it would certianly be a massive step in the right direction compared to the standard power output that just doesnt do the chassis justice IMHO
Depends how you like to drive, I like rwd cars to have enough power to make them loose, so a set of 888s and only 255bhp in a 1400kg car isnt what I personally like, but we arent all the same obviously.