I can't offer a ride yet, but from my recent RV-8 buying experience (not yet complete, been a journey), here are some numbers and my perspective FWIW. First, I only have 200 FW hrs, 80 of which is glider, and only 20 or so is TW time (I'll have over 25 by the end of transition training, which seemed to be the magic number for some insurance companies as a reference if you do decide on a TW). My insurance quotes range from $1500-$2200 (and one at $3500) for an $80k -8 annually. After the first year it should be down to $1200-$1500 assuming I fly the plane and get a lot more TW time. I didn't get quotes for an -8A, so I don't know how that would have compared.
Training requirements per the insurance companies range from an approved CFI signing me off (no min time) in an RV, to 5 hrs of dual, to 10 hrs of dual. They seemed most interested in TW time but your overall FW time should make your mins relatively low.
Get some cheap TW time (endorsement is easy to get) then do transition training and the additional cost of a TW will be a drop in the bucket compared to owning/operating costs. After initial cost, hangar, insurance, maintenance, taxes, fuel, oil, overhauls, upgrades, what's a little more $$ for TW training. After flying a TW, I would never get a tri unless it was a -10. TWs were frustrating at first when I kept bouncing and got into PIOs, but I got the TW bug after flying a few and getting used to it.
Definitely worth it to at least get your TW endorsement before you make a decision if you can. You'll have a new appreciation for the rudder and some challenges/fun along the way.