[dale]

The two popular 'high downforce' shells to have are:
Montech Racer
Protoform TypeS

The Racer gives more turn-in than the TypeS, so can feel a bit edgier to drive. The TypeS has more mid-corner steering, but actually feels quite stable, which has made it a very popular shell. It was the most popular shell at the BRCAs in 2018, and seems to work well indoors too.

The JP8 is a similar looking shell, but hasn't proved very popular. I tried it once and found it to be lacking traction.

(Post edited to reflect more experience of the available shells at the end of 2018).