Rear hub advice

I'll try and give as much information, but i'm fairly new to all these new terms so forgive me if I say something wrong.
I'm looking for a rear hub setup that is the preferably under $400 total.
I have a 2 mile each way commute for total of 4 miles round trip.
I would like around 25mph max speed on flats.
I weigh 150lbs, and I will buy a Mountain bike sometime soon that i'd like to put 26 inch commuter tires on. I'd like to balance speed/efficiency without feeling every bump.
The 48v 1000w kit from yescomusa looks like the best bet for me at $194 shipped.
http://www.yescomusa.com/Brushless_Electric_Bicycle_Engine-_48v_1000w_Rear_Wheel_Hub_Motor_Kit.html
As for battery I have been debating Lipo vs Lifepo4, I live in an apartment with seemingly no good place to charge up the lipo without risking burning the place down. If anyone has any suggestions for batteries that will give me the power and range I am looking for I am up for suggestions.
I have been looking at the 4s 4200mAh zippy's from hobby king, and 4 of them would put me at 52.8 volts and around $190 shipped.
http://www.hobbyking.com/hobbyking/store/__14067__ZIPPY_Flightmax_4200mAh_4S2P_30C_LiFePo4_Pack.html
I also saw that I could get four 4s 5Ah lipo batteries from there for about $100 shipped, but I'd have to factor in extra costs for securely charging. Well anyways, what do you guys think is there a different avenue I should be going down, or are there any costs i'm not thinking about?

Edit: Forgot to mention I live in Oklahoma, USA so the commute is relatively flat, there is one relatively steep hill at around 20 degrees but it is only like 1/8 mile long.

Forget the Hobby King LifePo4. Unless it’s radically improved, everybody who used it in the past reported it sagged badly and didn’t deliver labelled capacity.

Yescom motor kit is a great bargain and should fit your bill.

I can assure you many RC participants and enthusiasts buy and store RC Lipo in apartments around the world. Is it safe? Compared to what?

As long as my neighbor uses good judgement and handles RC Lipo carefully I don’t care if they have it in their pad.

Okay, so it looks like I should do some research into Lipo safety, i'll check out the forum for that, but if anyone has any handy links that would be greatly appreciated. If I go the Lipo route, I'm guessing I should go for 3 of the 4s1p 14.8V Turnigy 5Ah batteries for total of 44.4V? or 4 for 59.2V? Also what other costs would go with Lipo, obviously a charger, what is the best value for money considering safety for these? Also for keeping track of voltage/charge level during riding what would I need to buy that isn't too expensive? I'm assuming you need to keep track of them and not drain them or overcharge them correct? What do you think the effective range with that setup would be? Thanks!

I've got over 15K miles on a kit just like that one. For a 5 mile range you aren't going to beat rc lipo. 2 5000mah 20C 6s packs in series for 12s will get you about 6 miles at wot of ~28mph and won't stress them at all. I wouldn't worry about anything with them, but if you are, get an ammo can to store them in. In over 4 years of using rc lipo, I've never had a problem.
Lipo abuse testing;
http://endless-sphere.com/forums/viewtopic.php?f=14&t=27241

Thanks wesnewell, reading your posts is where I found the yescomusa link. Any recommendations for a cheap reliable charger for those 2 batteries, and what brand would you recommend for the Lipo?

Well 2 of them will be 222wh, so if you want to charge them in 1 hour, then you need a 222W charger. You could charge them in under 5 hours with a cheap 50W charger. So how fast do you want to charge them?
I like Turnigy over zippy.

I can't recommend lithium cobalt (Hobby king lipo) for an apartment dweller. But it could be possible, perhaps you have a balcony you can put a grill on, and store and charge them out there.

Much depends on the size of the pack, regarding safety. Small pack you have planned, easier to keep safe than a big one. Just like the helicopter owner likely doesn't have 4 ammo boxes filled with the stuff. Your short ride will only need a couple packs. It must be safer than my 30 pounds of it.

Just come up with a strategy for how you store it, and how you'll get it chucked out the window or door fast if you need to. The fire bags will only buy you a few seconds to act. Personally, I keep a flat shovel handy. If one of my packs goes, the ammo box it's in will be too hot to touch.

You only have to travel 4 miles, on flat land, and you only weigh 150 lbs....and only want a max top speed of 20-25 mph...

a 1000 watt - 48 volt rear hub motor is overkill for your needs.... and more complex then you need.

Keep it simple and cheap and safe { since you are in a apartment}

THIS IS HOW YOU SAVE MONEY..SPEND A WEEK GETTING PRICES OFF EBAY VENDORS :

If the 48 volt - 1000 watt rear hub motor cost $200 shipped....see if you can get a 500-750 watt front mount motor - 36 volt for $150 - $125 shipped. You dont need a rear hub motor nor do you need 1000 watts - 48 volt motor. The front mount motor will be fine for you and its EASY to put on or take off.

Next,

Battery - Since you admit you are NEW to this ..I would suggest a 36 volt- 10 A/H lifepo4 battery..that comes with BMS and charger...once again, check on ebay all week..compare prices..you should be able to get this complete package for around $250 - $300 shipped...it will be safe and come with everything you need , and have the power you need for your light bodyweight/ 4 mile commute. I dont recomeend newbies to start using lipos right off the bat, unless they are willing to take
all the time needed to learn about lipos and their dangers . For newbies, lifepo4 is almost always the best way to go.

Now, you must keep in mind, that even though this setup will save you money...it may not suffice if you decide you want to start commutting 20 miles per day...riding trails or large inclined roads....but for your stated needs, this setup will work .

to give you a idea of why a 48 volt - 1000 watt hub motor is overkill for your needs...ill tell you my stats..

I use that same hub motor from yescomusa...with a 48 volt / 20 ah battery...and I weigh 240 lbs...total weight of my bike is 70 lbs...for total weight of 310 lbs...and it pulls me at 33 mph on flat land.. for a distance of around 40 miles. you dont need that kind of speed or travel capacity...for your needs, you can go with a very easy and simple setup of front mounted 36 volt Direct drive hub motor of around 500 watts...and a 36 / 10 ah lifepo4 battery .