My late 08 is getting pretty laggy and need an upgrade. I want a 15in and figure 16 gigs and 2.3 since I plan on keeping it for 4-5 years and think I need the 512 so should I just get the dGPU even though I know I don't need it. Anyone know if it will significantly lower the battery life or increase the heat? Unless its a significant different I feel that I might as well get the best I can. This has been holding me up since the late 2013's were released and I really want to get one soon.