I have found no drawbacks to the 1.8 intake cam. It feels the same at lower RPMS (sounds more growly though) and it seemed to raise the peak power from 5100 rpms to just north of 5300

 

Hmmm... 5100RPM? Sounds a little low. I guess thats close if it's stock and then you swap to 1.8L. The AEM Intake dyno moves the peak power from 119whp@5300RPM to 124whp@5600RPM. The more n/a you go, the higher the RPM band moves. If its a fourth gear pull, most dynos are, with the AEM you would generally shift at about 5900 for best power. Anymore than that and torque falls through the floor. I never knew torque fell so much after 5000RPM.