2007 Scion TC Turbo

I'm looking to purchase a Scion TC that has 44,000 original miles. It's turbo and he wants $6500 for it. I'm wanting to know if this is a good deal, I've owned cars that have been turbo, but they were all factory, I know nothing about Scions.

I have a couple of other questions:
The car is running a piggy back, could this be used to disable the CEL for emissions? Any guides anywhere?
There is the common idle issue after driving it hard, the owner has taken it to 3 different tuning shops and it still exists. How can I fix it?

Those are the only problems it has.

Here is more about the car:
Turbonetics GTK550 Turbo, Turbonetics RG45 Wastegate, Turbonetics Godzilla BOV, Custom Aluminum Intake Manifold, Custom Stainless Exhaust Manifold, Custom Baffled Oilpan, Custom Intercooler and Piping, Custom 3 Inch Tig Welded Exhaust with Magnaflow Muffler, Apexi AVCR, Split Second AF Box, Willwood Big Break Kit, Driveshaft Shop Axels, Stainless Braided Lines including Oil and Vacuum, Tein Basic Coilovers, Walbro 255lph Fuel Pump, 28 ln Secondary Injectors.

Engine:
Eagle Rods, Race Rod Bearings, CP 9:1 Pistons, Upgraded Retainers, ARP Head Studs

Interior:
Alpine Double Din Nav/DVD Headunit.


I've seen all the receipts and there is 10 grand in the motor alone. I know you never get your money back, but the car inside and out is super clean, and the engine bay looks great, like the fabrication looks good and everything was placed in all the right places.