The OP has entered the real world of: "The Laws of Physics"...
Boy racer stuff...mainly...
Wider stance does increase the stability in curves and turns...especially during high speed maneuvers
Stiffer/stronger sidewalls is wanted for lower slip angle and the above, better handling on curves and corners (high speed for both)
Yes, they will ride a 'bit' harsher, but well worth it to those who have performance higher on their 'have to have' list...over ride quality
Yes, wider stance will have better moments to handle those cornering/curve maneuvers and as mentioned...increased moments will also create higher loading on the suspension parts...mainly the bearings
If the OP also changed the wheels, they might not be stock offset, which if more negative offset...will increase the track even more
Why did the OP go with 2" spacers in their re-engineering of the suspension/wheel/tire setup?