I have been following the TJ08-E club thread on OCN ever since it began and I have seen more than one person attempt that same cooling gizmonodo approach. If I can recall, he also reworked his loop...
1| the TJ08-E was meant to be an awesome air cooled rig not an internally mounted watercooling rig.
2| reason I'm using a discouraging tone with your project is due to the fact that the front 180 will dissipate heat into the case due to the fans orientation and the rear 120 will inturn pick up heat from the front 180 and then warm up your loop raising your waters temps. Don't forget to account for the other components that may heat your case innards.
3| that TDP+overclock aren't looking so good in that case with a limited watercooling option.
you've followed all the posts and all the pages on OCN regarding that club+case...you'll find out how disappointed those watercooling it are. Likewise, those watercooling it aren't seeing that sweet spot setup from a crippled watercooling loop. Non of them admit it(maybe one did and reverted back to air) but they weren't expecting decent
from an expensive setup. In your case, it'd be a waste of good money which could go towards an awesome loop.
5| Keep the whole case on air and have the CPU only off of watercooling like a Corsair/Zalman/CLC unit if you must, but I can see a Hyper 212 beat it hands down in such a tight space
To answer your threads questions, the 450 isn't a good pump to begin with and the pump would eventually fail when it'll be dragged across restrictive parts across the cpu+gpu blocks. I'll also couple that the case being tight in nature will require you to add degree'd fittings which'll add more restriction to your loop/pump -> aiding it in its demise.
Tell you what? head down to the watercooling sticky and read it patiently, you'll get a good grasp of where my notes are coming from, would provide an amazing insight into the world of watercooling and will help you narrow down what you'll need.