Worth upgrading from 4670k?

Cool i will check it out

Looks good except i don't have a vice at my current house

Haha, well dont let that hold you back. While I find it difficult to believe that you do not know anyone in possession of a vice, there are cpu delidding kits that work in the same manner; made just for viceless people, or those untrusting of a vice :Þ

Of course, friend/school/hardware store with proper tools would be the more economical route.

Ultimately, its up to you, but I personally will push a CPU if an extra 500-700MHz OC staves off the need for an upgrade. Aside from VT-d and better TIM, clock speed is the only difference between Haswell and DC.

PS: About delidding, it's a simple task, but the rabbit hole goes deep, in terms of what TIM to use(most people use Liquid Ultra, but that stuff is conductive AF). Results for 4x70k skus range between 15-30c reduction (depending on how poor the factory application was on your CPU)

I'm on Haswell currently (i.e. i7-4770K). I had built a friend a Kaby Lake system. IMO TBO the improvements are not noticeable and minute at best. If you're looking for more raw power I would suggest upgrading your current processor. That's way better than having to purchase a whole new motherboard, RAM, and CPU.

In a different thread someone was suggesting the i7 5775c. It seems pretty interesting. It is more expensive than the 4790k but has way more cache and slightly better single threaded performance iirc.

but it sucks for overclocking. Like 4GHz max.

If I'm not mistaken, your z87 board will not be compatible. Also, intel went on the books to say the Broadwell memory controller has a voltage ceiling of 1.35v. If you have one of those 1.65v kits, you'll need to replace, or severely undervolt them.
Stick with the Haswell family ;)

Thats correct.

I think that i mentioned that above.
But indeed Broadwell cpu´s are not compatible with 8 series chipset boards.