upgrade to a 3.0SC - 3.2 barrels, inlet manifold and injection
 

ok, so i was told about doing this to a stock 3.0 but i'm not very mech minded. what does it mean and is it advisable? That is replacing the existing stuff from a 3.2... i think.

Going to a 3.2 from a 3.0 requires increasing the diameter of you cylinders to 98mm as there is a stroke difference between the Carrera 3.2 and the SC 3.0. 3.2 cylinders are 95mm without a head gasket and 3.0 SC cylinders are 95mm with a recessed head gasket. Most people recommend twin plug conversion at this point (98mm P/C's).
To change from CIS to stock 3.2 Motronic fuel injection would require swapping out the flywheel for the crank sensor (and notching of your tranny to match), heads for cylinder-head temp sensor (or some modification to fit stock sensor) and matching of intake ports to the Carrera intake manifold.
It would be far easier to go with an EFI kit like the Tbitz kit

can this sort of thing be done as part of the rebuild process?

correct me if I'm wrong but putting carrera 3.2 Pistons and cylinders on a SC crank creates a dog and is not advised.

911SC 3.0 is a 95mmX70.4mm bore/stroke
Carrera 3.2 is a 95mmX74.4mm
911 C2 (964) is a 100mmX76.5mm
3.2ss 98mmX70.4mm

The simplest would likely be a swap to a complete 3.2. On the other hand, if you are going to swap, why not a more modern 3.6.
I upgraded to 3.2ss (short stroke) when worn valve guides necessitated a top-end rebuild and I was in the mood for a large project. I opted to convert to EFI using a Carrera intake but an aftermarket controller (Megasquirt). I sourced some inexpensive used 3.2 heads to match the intake and had them rebuilt and twin plugged. The use of Megasquirt also gave me the ability to run a distributor-less twin-plug ignition.
The more stock you keep the rebuild, the less time you will have to invest. An EFI conversion like I did was far more complicated than an engine swap and very labor intensive (tuning is a huge time commitment) but has the advantage of giving you great flexibility for the future. I think trying to swap out just the top side of a 3.2 would not yield you much for your efforts. If all you want is the EFI then keep your existing CIS intake and convert to a Tbitz EFI. It would likely be easier and less expensive although I don't have any personal experience with that kit.
If you are in the need for a rebuild then you have the ability to do just about anything limited only by time and money.

I may be missing it, but weren't you (Mondo) asking about swapping injection systems from the 3.0 CIS to the 3.2 system?

It would be easier if you tell us more.

You want to use DME from a Carrera 3.2 and replace CIS on your 3.0.?

You want/need to rebuild your 3.0 liter?

You want to increase displacement by using 98 mm P/C's as a bolt-on option for the 3.0 liter making it into a SS 3.2.?

You want to keep CIS for the SS 3.2.?

You want to change cams as well?