I sent mine to Fastman last year to get the standard front only mod done on mine. It was only a week turn around to get it back. If you can not have your car down that long, call him and have him send you one that is already modified. I have not had any problems with it. It is a real easy swap, remove the intake tube, unplug the connector then remove four bolts. But be careful putting the bolts back in because they screw into plastic.Look into Fastman TB's. You can send him your stock TB and he will port it for you. Supposedly better than aftermarket TB's and a lot cheaper. Install is fairly simple, just removing the intake tube and he 4 bolts from the TB.
This modification to TB plays real nice with a tune. I would do both because it will really wakes up your car.
The stock 80MM body has plenty of flow for the 5.7.
5.7L 6.1L 6.4L Hemi V8 Throttle Bodies - The Fastman