Yea i want to but im still not 100 sure i want to buy it.
(1) What is the different between the regular 510 and the ego besides the big ... battery?
(2) And The 510 manual batteries are sealed off too right?
(3) And the 510 atomizers fit on my blu too?
(4) so the blu ones can work as spares?
1) The eGo battery will last several hours longer before needing to be recharged. Instead of 1 or 2 hours of battery life, you'll get 6 to 12 hours of life, give or take, depending on how many drags you take. The eGo is only about twice the diameter of a 510 battery, I believe. After you use it for a day or so, you won't think it's a big ... battery.
2) Yes, anything that says "manual" is a sealed battery, so juice won't leak into the battery and kill it.
3) Yes, 510 atomizers and cartomizers will fit on a blu battery.
4) Yes, the blu batteries can be spares. However, I have Volcano batteries (similar to blu) that I'll never use again, even though I originally thought they might be considered "spares."
You don't need to buy an eGo kit. You could buy one eGo battery and give it a try. All the 510 parts you have will work with it. There are many suppliers who sell individual batteries for about $16 to $24 each plus shipping. There might even be 650mAh eGos available for around $12. Someone else might know where to find those.