I wouldn't sweat the modded SRTs... 90% of the mods people have installed are 'external' to the motor... meaning the integrity of the engine should be the same/similar to the stock-as-a-rock SRTs with similar mileage. I bought mine with the NW single, EC tune and 65mm pulley installed... 12.3 the first time I ran it. best part, I paid the same for this car as I would have for another SRT in stock condition.

As for the Plasti-dip, I've simply seen too many train-wrecks in person. Professional examples exist, but the same can be said for crushed velvet interiors. As with anything, if you do it properly you'll get good results. It's all in the technician applying it, and the prep-work.