Just to give some perspective on the performance you can expect...
Here's
JoeC's review of the MCX462+T at Overclockers.
The MCX462+T uses a 226 Watt TEC.
A 150 Watt TEC and an 80 Watt TEC gives a total heat pumping capacity of 230 Watts.
The MCX462T has only a coldplate between the TEC's coldside and the CPU.
The setup being discussed will have two waterblocks between the TECs' coldsides and the CPU, but a bit more TEC surface area.
I'd guess the setup being discussed may give performance similar to the MCX462-T. Quite possibly worse.
Worthwhile?