Those are forged. Forged have the flat smooth'ish parting line, cast is a thin ridge parting line. Below is a comparison of a cast (left) and forged (right) rods from the same type of engine.



As for compression. What I'm always told is, particularly for small engines (I count these as small..) is low compression will make them feel underpowered and lazy at low rpm, where higher compression will make a bit more HP/TQ off the line before the turbo spools, making a more even powerband/feel. I agree with your machinist on that 8.0'ish compression will be easy on your fuel bill and live happily on 87 octane "most" the time depending on boost levels. Getting up around 9.0+ compression will require premium fuel just to be sure you don't accidentally ping the engine when boost comes in, particularly at low rpm. If your turbo is sized right, boost can come in fairly early in the rpm range and low compression can be a near win-win IMO.