Mattias, having done this event twice, I hope you realise it can be very tough, even the D class, if your not used to it. Your navagation skills are really tested as is your route 'choice'.
If you decide to do it best of luck, but stick to your own pace and enjoy it. You don't have to win the class you enter first time out!!!
The times I took part I was just happy to finish, never mind trying to win!!