4? Will I need to remove all of them to secure the cams? I thought that with the tool you only get one or two cam lockers

You will need to set the engine at zero timing. The cam "lock" is really a cam adjusting / alignment tool. If you wanted to prevent rotation for both sets of cams you'll need two sets and they are not cheap. Some of the more experienced members swear that the cams have to be locked with the adjusting tool at TDC or they can rotate. I'm not as experienced but as the lifters are all sitting on the cam circle at TDC I don't see why they would move. They didn't for me. If you are going to change the IMSB you'll want to retime the valves. That is 4 plugs.

There are some really sad threads of dealing with an IMSB change that becomes a disaster when no cam locks were used. Very expensive because you may not discover the problem until you try to start the engine.
You can make your own cam locks from steel plate. The adjusters are another story.
A complete tool kit is less than $300 and easily resold.

Enlighten me, and everyone else. Please post a link to a sad thread where cam locks were not used. Not a sad thread where timing was not set to zero before dis-assembly as those are unfortunately far to common. And since I have an M96.24, the earlier engines, unlike the '03 and later engines may have separate locking and adjusting tools as you imply above. It would be helpful to the forum if you could describe the differences in the two tools. I've tried to make my own '03 cam alignment tool, and I'm not a complete idiot (only half), but without a machine shop, it is very difficult, and after buying a commercial version, the tolerances between 5 separate points in 3D space are extremely tight. ;)

This may be helpful :
http://986forum.com/forums/performance-technical-chat/56166-m96-camshaft-timing.html
http://www.renntech.org/forums/topic/47231-locking-cams-really-necessary-on-an-ims-replacement/?hl=%2Bcam+%2Blocks#entry259081
There is plenty more if you search
Tools pictured here:
IMS Pro Tool Kit. Everything you need to install a classic Single or Dual Row IMS Retrofit. - Featured - Products LN Engineering

So if I buy the complete tool set it will have everything I need? I read that the tool set comes with 2 locks,one for the 5 chain engines and one for the 3 chain. So as far as I can understand,I could only use one cam lock. Will that be enough?

Timing
 

Yes, you only need one lock. You only do one side at a time. Then rotate the engine.
Set the lock on the other side of the engine and re-time that side.

350 USD for a tool kit that you use only once is a lot of money. OK, maybe you use it twice, but still a lot of money.

If you have access to a milling machine and someone who knows how to mill and weld, you can do the tools for a fraction amount of this. No rocket science. Just my 2 cents.

Regards
Markus

I thought about that to be honest, but since you need the removal tool, the insertion tool,and the cam and crank locks I think id rather have the whole set as professionals intended,especially since I don't personally know anyone with a milling machine. The most logical thing would be to buy a second hand tool set,but I cant seem to find anywhere.

I read somewhere that on the 5 chain cars you only need to lock one side, the 1to3 cylinder side. Do you suggest I lock the other bank of cylinders as well?