What are some good anti-theft iPhone apps?

I'll be buying an iPhone tomorrow, and in the past I've had way too many stolen.
I don't want this to happen again, and am looking for apps to help prevent a thief from stealing my phone.

What I'm really looking for is an app that will continue to work if the SIM card is removed, and will disallow someone from uninstalling it from the phone.

Can anyone make any suggestions?

Whatsapp installation and activation?

I have an iPod 5 and I want WhatsApp so I followed the installation part but the activation requires an iPhone I'm studying abroad and I don't have an iPhone nor do I want to ask someome for theirs (don't know that many people) can I activate it somehow else? I'm not willing to jailbreak it either!

How to clean up my iPhone 4s and speed up it?

I bought a iPhone 4s as soon as it published on October, fourth, 2011. Almost three years have past,
It gets old, too. Sometimes It needs several minutes to wait its reaction. And I become more and more annoyed. As an academician now, I can't afford a new one. What solutions do you have? Oh, so bored.

Is music from apps other than iTunes restored in a back up?

I was grounded for 5 weeks with my iPhone 5c powered off. When I turned it back on everything was fine but it said it needed a software update. Then told me to connect to the computer. In doing so an alert popped up saying my phone needed to be reset to factory settings and then I could restore to the latest back up. I have music through a music app (1000+ songs) but its not iTunes. Will I get that music back or have to redownload it all?

Why is my message not delivering?

This girl I like that I work with I'm texting, we both have IPhones so it's IMessage, and she told me she's up in Milwaukee tonight for a college orientation, we live in the northwest suburbs of Chicago. Milwaukee is about an hour and a half car trip up I-94 from where I live. Why is my message not getting delivered, is it cause of the distance? Like she texted me I sent one back as soon as possible, and then she texted me right back as well, but when I went to send the next message, it is sent but the delivered thing isn't showing up? What's going on?