Ahh but I walk into the store I say hey I need some things he says ok what ya need I give my list:
I buy the Response parts for 4k (rating 5)
the Signal parts for 1k (rating 5)
I buy the Firewall parts for 3k (rating 6)
and the system parts for 3k (rating 6).
He says ok thats gonna be 11k. I say thinks now I got a commlink he says to me son you need a case to put all that in here I'll sell you one for 100 I say ok thanks and walk out.
I go home I make a commlink the has the stats of 5/5/6/6 for 11,100 nuyen SURE it runs at a level 5 system (untill I can go back an buy the rating 6 response and signal). BUT it is also upgradeable buy 2 levels from here. Which would allow me (once I buy the upgrades needed) to have a system of 8/8/8/8.
THERE is nothing that says I can't buy the parts and build a rating 6 commlink then upgrade it.
If, and only if, your GM agrees that the component parts of a commlink are nothing more than a pair of upgrade modules for an existing commlink and a 100¥ case. Since the RAW doesn't establish any of these equivalencies, your home-made commlink is purely a thing of the GM's whim.
Also, I direct you to the following:
To create something, a plan, the proper materials, and time are still needed.
Technical skills do not allow a character to create a new item/device from concept alone - that requires something along the lines of an engineering background and lots of collaborative effort.
Translation: Unless you have the drawings and procedures required for a 5/5 commlink, you aren't building one with just the Hardware skill. To build, from scratch, your 5/5 commlink, you need to first develop a 5/5 commlink schematic using appropriate knowledge skills and a lot of free time.
EDIT for grammar and spelling.
