But the only differenz i can find is the capacitor, that seem to be more bigger in the VX450.
But at all, i find out that my soldering iron is broken. 
...luckily for you since you really shouldn't mess with that PSU of yours. It's mostly the bridge rectifiers and power mosfets one needs to worry about in a PSU.
You won't find any obvious differences between these because they come in industry standard packages (e.g. TO-220).
You need to study the datasheets to learn the exact specifications.
The fact that you're not even aware of this is proof positive that you shouldn't think of tampering with the PSU.
BTW, capacitors are merely used for filtering and ripple suppression.
Replacing that "grain silo" will not increase the output power.