Depends what you are looking for I fitted them on the advice of Tweenie after telling him what I was loking for from my car. Told him I was looking for high 5 hundreds hp but still good driveability. He said type B poncams were the 1s to use. Ideal.
Ref shims. Can't really say as my head was off & had new ex. seats all new guides springs o/size valves & new greddy springs + seats re-cut so obviously had to re shim
Heard that you don't have to with these cams but only measuring will confirm.
The whole point of EASY/PON Cams is 'easy' drop-in. They have the same base circle size as OEM Camshafts and do not require shimming.... if you have a virgin/untouched Cylinder Head that is, although, you should always check clearances just to be certain.
I was also looking into these as well in addition to the Tomei valve springs (type A). Is it pointless to upgrade the cams unless you have to do machine work to the head? Sorry if this is a noob question.