Should I use the PG Octane-R 5.0:4 (150 x 2 watts RMS 4 ohms) or keep my Diamond D3 400.4 (182 X 2 watts RMS 4 ohms)? The components are said to handle 140 RMS on the website.
Here are two more to look at. Both are 150 X 2. PPI DCX 300.4 and Diamond D5 300.4. Only problem I have with my Diamond D3 400.4 is that it might be too much power for the EF's
It won't be too much, just be careful with the gain settings. The PPI DCX series isn't all that great, if you want PPI their Art series and PCX are good.