A fast action 7wt would definitely do the job for most streamers. If you use insane 20cm long streamers then maybe an 8 would be better. 7wt would be on the light side for 80cm pike, but if you buy a good rod and use heavy line, you can lean into the fish and work it in faster.
Regardless if you choose 7 or 8, fast action would be my recommendation would be the
Loop Evotec cast which is not too bad on the wallet either for a high quality rod. Loop makes a great rod. Others will say different though.
Just my opinion, and good luck.