Offhand, I'd guess the weight and balance of a Spoiler 5 may be an issue for you before any noise, Craig... seems like I recall you've had at least one of these before, but from personal experience, my Persuader 5-string is the heaviest of my Alembics, and the most neck-heavy at that. Not insurmountable for me, at least not yet.

Hopefully you can try it out first.
On the subject of RF upgrades, every single one of my Alembics are dead quiet, except my '81 Distillate... it is the only one that ever experiences any high frequency interference. I so seldom ever open the filter that far that it isn't much of an issue for me playing out anywhere, but it's definitely there. I've been thinking lately about a trip out to California to visit the Mothership and just bringing that one along for it's first journey home in nearly 40 years.