If i decide to not connect the spindle to the power supply and the plug the spindle into a wall outlet the electronics wont short out right?
Short answer for stock spindle… NOOOOOOOO! Don’t do it!
You can obviously use nema 23 on the x carve (269 oz). But the requirement for 425 oz nema 23’s are no where close to to the 269 oz version. If i wanted to connect up 425 oz would i need to change any of the electronics to make it run. Link to the 425 oz, specs should be there if you scroll down. Ps: thanks for all your guys help, i am new to this cnc stuff 
http://www.ebay.com/itm/US-Ship-3pcs-High-Torque-Nema-23-CNC-Stepper-Motor-425oz-in-4-Lead-DIY-CNC-Kit-/231596049990?hash=item35ec334646:g:R-0AAOSwT6pVjp5E
@JonathanLee I just bought some motors from the same company. I got some much smaller nema 23s. It took forever for them to ship, but the motors seem good.
The rated current on the ones you are linking is nearly twice what the gshield can handle, so you would absolutely need something other than that.
If you are set on those exact motors, they are $12 less after shipping on their main site than on their ebay store. http://us.stepperonline.com/3pcs-of-high-torque-nema-23-cnc-stepper-motor-113mm-3nm425ozin-23hs454204s-p-397.html
For reference, here are the ones I ended up getting http://us.stepperonline.com/3pcs-of-nema-23-cnc-stepper-motor-28a-126nm1785ozin-23hs222804s-p-395.html
So i barely know anything about cnc machines. If i wanted the 425 would a tinyg board work. Does the tiny g replace both the aurdino and gshield? Im using this on a 3040 cnc so the y axis only has 1 stepper motor, Do you think the 269 oz is enough power. The weight of the 3040 cnc design is pretty beffy and on top of that i also plan on putting a 1.5kw spindle or a dewalt router.