I've not heard that many great reports on the Forge jobbie, so I can't see a cheap copy being a good choice. (I've never tried either so can't give you my own experience)
If you've got a stage 2+
Cupra why not look for the best system you can get, yes they are expensive but why cheap out on what's a fairly important piece of kit.
The main reason the kits are so expensive is due to the huge amount of R&D that goes into them making sure they are as good as they can be.
I took a fair amount of time before I settled on mine, but I'm so glad I didn't buy a cheapo kit.