the website says the 3500 comes with a back battery cover with their logo on it. anybody that has ever ordered a battery that required a bigger battery cover from Seidio, what does it normally feel like (soft touch/plastic?) and how much bigger is 3-4mm --i just cant picture it in my head. and how much bigger does it feel--like is it really noticeable? the only issue i have ever had with my eris is the battery but if it is tha noticeably different then i may get the 1750mAh.