OK. Will any battery straps do or should I get some G-Maxx straps. I have some velcro that I bough from Wal-Mart which is pretty strong and would save me $10.

Anything will work, but align has some straps for about $4 that work fine.

Ok I just don't want my Battery flying out at 40mph...

Can't blame ya. I ruined a lipo that way, except it was at 60mph.

I guess Ill just get some super strength velcro. A 70mm Medusa would be best right...

Depends what you're looking to do. My 70mm throws around my 12lb truggy like it's a ragdoll and runs cool to boot.

Ok I guess the 70mm it is.

Should I get the 1600kv or 2000kv for 5S. The 2000kv seams like it would be better but wouldn't the 1600kv be better because I could just gear up to get the speeds I want?

Well,
The motor is a 6XL 2800kv so it looks like I can't use it on 5S. Even running it on 4S would be pushing it. It looks like selling it might be a challenge... I think I'm going to go with the MMM Medusa Combo and run it on 5S.

I'm starting to think I should just keep the RC18T and save up for a ERBE or just go straight to a 1/8 Truggy Conversion.

Just get the MMM/2200 combo and run it on 5s. I ran a lst that way and got great temps and runtimes, all on 4900 20c rhino lipos. I am very impressed with the cc neu motor, I think it is better than the medusa 70 and 80mm motors. Plus if you are careful you can get a brand new 2200 cc neu on ebay for around 125 shipped. And it is designed to be a car motor, so you do not have to seal it up or worry about needing a front cover (all of that adds cost).