I've just replaced quite a few 400W MH with two 50W LED each. I did not want to do a conversion. You can buy the LED cheap on Ebay and (depending on your electricity cost) can get a return on investment of 4 months. I decided to buy them from my local shop: My ROI will be around 12 months. That's good enough for me. It looks different. Everything looks "cleaner" - more upmarket. I did not get anything from my electricity company.