My take on this one as an SVO owner-

I don't think they're going to appreciate as well as the V8 cars, honestly. If it had been a good bit faster than the V8 cars out of the factory, then things might have been different. Look at the Turbo Trans Am in 1989 (I think). Limited, smaller motor than the flagship model, but definately performed in a way that earned respect. SVOs didn't do the same thing.

I've already noticed that clean (and more stock-ish) 87-93 V8 cars are already starting to really go up! They're not even as old or rare as the SVOs, but I'll bet that their rise in price has something to do with the fact that more people have fond memories of 5.0 cars because EVERYONE had one back in the day. Now more of those people want a nice stocker again for weekends or whatever. There's your demand.

SVOs on the other hand... Fond memories include:

-Having paid a LOT for a 4 banger back in the day
-Limited aftermarket parts
-Probably some service nightmares (did anyone know how to REALLY work on them?)
-Always having to show up the V8 guys...

I couldn't imagine trying to tune one of those back then! We're pretty spoiled now with readily avalable widebands, data loggers, tuners and standalones nowadays. In a way, SVOs are great cars to have now, since the turbo car/tuner market is so healthy.

I have an SVO as a daily driver and I still love it even though it's beat to hell and I've had it for 10 years.