Re: Need some advice
I would say that you are good with what you have been doing with the 4wt, and could even fish for some large trout/bass, they would just give you a good run for your money.
The 8wt would be too much rod for anything but the largest trout or bass. I've never fished for pike, so someone correct me if I'm wrong, but you could use it and do OK unless you hooked into a 3+ footer. Just make sure you have a pike leader which is metal as pike have very nasty teeth.
I've known people to use 8wts to go carping, if your interested in that.
Whatever you decide, welcome and good luck!