Jer7of9,
There is no catch , Our new TRIDVR-EL16ME4, and TRIDVR-EL16M4 will work with up to 4 MP HDCVI, also a great feature on this upgrade would be the ability to add up to 8 IP cameras at as high as 4 MP making this a 24 channel recorder. To go along with the recorders we have the new CVIOD-EL4IR and CVIOB-EL4IR cameras that you can use over any existing coax you have.
It is as easy as you are thinking it would be. Just swap the Recorder out and upgrade the cameras it will all work the same but will be in 4 mp. I am in sales and can help you put together an order or explain to you over the phone if you like on Monday morning when I am back in the office my direct number is 866.573.8878 ext 117.
With Regards,
Matt Ernst
Sales Rep