Even just a new fork is going to be more than the bike is worth. And a new fork won't pep up anything.

Carbon wheels will just give you better feel for the road. And that missing input could be what you interpret as having pep. But your actual increase in performance certainly won't be worth the ridiculous investment you just made in the bike.

The bike is a slug. Face it.

But also realize that riding in rain will make most any bike feel less peppy. The water on the road increases the rolling resistance. Or so I'd think. Not sure why you favor that bike for rain, snow/slushy conditions over any other bike. CF doesn't care what you ride in.