Do you think upgrading the kits 3-way switch to an Oak Grigsby or standard Fender US one is going to make a difference?
I have connected wires to it now a couple of times now and it is starting to look a bit hammered, that's why.
I presume you have the stock "import" type switch in there currently. Personally, if it's quiet, and working properly, I wouldn't. But that's just me. However if the solder lugs were looking gnarly with great gobs of solder, I would [have] thoroughly cleaned them off before soldering on my new pickup leads. With soldering, I'm of the opinion that a tidy looking solder join is also a better connection. Even if someone isn't an experienced solderer (?) I encourage them to try and be as neat as they can. FTR, I'm not an expert, but I can do a fairly tidy job of it.
Sorry, got sidetracked there...

Back to the switch upgrade...
There will be no sonic enhancement (ie: better tone). Different types of switches will have different "feels" because of the individual mechanisms used in their function. You may like the feel of one over the other.
More expensive units like CRL can certainly be of higher quality and may be more durable or reliable but ultimately they're all susceptible to wear and tear, corrosion etc. To me it's a situation of "if it ain't broke, don't fix it" (unless it makes you feel better ).

Another consideration is the depth of the control cavity. I can't recall what the cavity depth is on the PBG TL's, but CRL and O-G switches are taller than the import ones therefore may require routing the cavity deeper to accommodate them. If the cavity is shielded, there can be short to ground issues without proper clearance.