Summer/extension classes @ UC before application

<p>Did anyone here take summer classes at a UC before applying? I want to take some upper division classes in my major at UCB this summer before I apply in fall because I think it will give me a boost and make up for my subpar GPA. Did anyone have success doing this? Do you think it helped get you in? Will I have any problems with a unit cap if I'm just doing summer or extension classes?</p>

<p>I'd also like to take some UCB extension online classes but I'm afraid to take too many and put myself over the 80 unit cap. Do you think it will matter?</p>