So hard to keep a thread clean and bite my tongue. Any way....I think most people are reluctant to get mods done basically because it's a bit of a roulette spin, you might bet lucky you might not, but if the detector performs less well then your also out on offloading an older detector for an upgrade. The 4500 is pretty darn cheap at the moment with warranty and a variety of coils and options inbuilt to achieve better (possibly) results than stock settings and coil options. Even new coils aren't exactly high ticket priced items. Or hand your well earned over to someone and hope you get the good end of the deal.
Mods like the fix to the SPP hiccup issue are widely accepted, but potentially turning your detector into something less usable probably won't appeal to the masses.
If you have the cash to spare and an open mind I say go for it, might turn out to be great investment.