Welcome to the forum.
First, go back on this part of the forum and you'll see a few threads on pretty much this topic.
One of the regular bit of feedback from the experts is to try to spend more at the start, because if you like it you inevitably want to upgrade from budget gear pretty quickly.
The $400 you spend now would be pretty handy a few months down the track towards the $800 combo you now want!
Also, you'll see a debate of shorter rods (more practical for out of the boat) versus long rods (usually better off the rocks, for a few reasons); and debate about the need for powerful drag versus lighter drag. Some people say you need to lock up and hold on off the rocks, others say better to go lightly and the kingie will cooperate.
I think part of the answer for you is determined by where you intend to fish. That indicates the likely size of fish, the terrain, and therefore the rod/reel/braid which will suit, and the lure size.
Off the rocks at the tip of Coromandel, or up in Northland, I reckon with a BG5000 you're taking a knife to a gunfight.
But if you're going off the East Coast Bays rocks, perfect.
There's a big difference in weight between the BG5000 and the 6500, which makes a difference after a few hours casting off the rocks. The Shimano Saragosa is another good mid range one to look at, maybe in the 10,000 size.
In terms of rods at the lower end, I strongly considered buying a Penn Assassin, which has great components and felt good in the hand. In my opinion, it's much nicer than the Backbone.