True, it is possible to play on the laptop( I have SH3+GWX on mine)
Everything depends on the graphics and ammount of memory, especially on higher TC.
But to answer the original question: your machine wont be more stressed after you install GWX with one exception - there is WAY MORE traffic in ports so on low spec laptop leaving the port might take you quite some time as it will be slow and extremly laggy.
Hope that helps
