The permission read contacts is used for detect missed call. You can check the source code on my github to make sure this app don't read/send your contacts data.

NSTools need superuser (a.k.a root) and also custom kernel with Ezekeel's mod.

Currently works on:
Nexus S (kernel: GLaDOS Matr1x franco SG-kernel Eugene Trinity Netarchy Lucid Air Lynx etc.)
Galaxy S (kernel: Glitch v14)

With NSTools you can easily manage these tweaks:
- BLD
- BLN
- BLX
- CPU Governor
- Custom Voltage
- Deepidle
- Liveoc
- Max/min scaling frequencies
- Touchwake
- CMLed
- IO Scheduler
- Fast charge toggle

Your settings will stick on reboot don't need to edit init scripts.

NOTE:
If something bad happenned and you want to reset NSTools settings visit my thread on XDA to get reset_nstools.zip

Please don't report/complain bug on comments because I can't reply your comments. Send me an email or visit NSTools thread on XDA

source http://github.com/arifhn/NSTools

Thanks to Ezekeel for all his mod and all great people in XDA forum