All good points. Having one fairly extreme version in my supercharged LS3 Coupe and the more simple LS2 vert, I have a new perspective. The LS2 charity car is really fun to drive, with more usable power and the auto tranny. Believe it or not, it is the latter that really makes the difference. The shifts are crisp and simply mashing the pedal is all that is needed to enjoy the fun. My Coupe is getting a brand new T6060, clutch, etc., which should shift much better than the used GTO tranny that went in, but the auto is super fun.
Rob is right on the journey -- the charity car, with only 10,000 miles on it, needed more than a dozen hours on the tune, new headers, cats and exhaust, plus a bunch of stuff that was never addressed initially -- new air intake, bigger wheels/tires, custom coilovers, front brakes, underbody bracing, stereo and A/V upgrades, new leather, new exterior wrap and a handful of smaller fixes. I have said many times, if one can find a good price on an existing conversion that is clean and has knowledgeable people who can work on it, they are fun little monsters.
This Blue Monster LS2 car is fully sorted and needs nothing. It passed emissions easily and is ready to roll. But it took some time to get there.
Back on topic, if you can find a clean car to start with, new conversions are still a lot of dough. New LS3's are still 6-7K and used ones are still very pricey. You could shop the Low Priced Solstices thread here for a donor car, but those will likely need a lot of money spent elsewhere in addition to the swap. To agree with Rob, there is not really an easy or cheap way into one of these, unless you can find a Mallett out there in the mid-teens from an uninformed seller (unlikely). Even so, there is always more to do and more to spend.