To me it is worth it.

The upcharge is a lot of money, but then again lets keep it in perspective with pecrcentages since the RT isnt a cheap car. Its a 20% upcharge to get the best features offered without the need to tinker.

I'm not buying as an investment, but im using history to help guide optimizing my choices including.

Best performance package
Loaded
Original - no modifications (at least no non-reversable mods)
Full documentation, history
Rarity (although not picking a rare combination, I hope there are very few SRTs in total)

My choices are because I choose to afford them. My #1 choice to buy an SRT is because I want it!