I am going to do a custom sleeve job on my PSU, I just don't know if it's worth the hassle to do it myself (it's a TX750M, which isn't fully modular) or should I just send the PSU to someone to do it for me?
Power cabling is fairly serious stuff so I'd say go with one of these alternatives:
1) Don't bother. Try hiding the cables as much as possible instead of taking any chances for the sake of estethics. If the case lacks decent routing holes then perhaps it's worth looking for a new case anyway.
2) Send it to someone who is known to have a serious workshop and electrical knowhow. Don't take any chances of some dude wo will do it cheap.
3) Do it yourself, but practice taking apart some old junk first if you aren't experienced already.
You can buy pre-sleeved cables from various websites. It isn't that hard but it is a lot of tedious work to do it yourself.
I'd do some extensions if I were you, and then sleeve your full PSU when you have a modular one. Not worth the work for a semi-modular. Extensions are universal, though.
For a PSU that is not fully modular, if you are going to do custom sleeving, you will have to take it apart, then desolder each cable, then sleeve them, then resolder. overall it is not hard, but it is tedious and boring work, and the end results do not look as good as expected.
Most of the photos that you see when the wires have custom sleeving, look better with good lighting, but once you have the side panel on, or in standard room lighting, it just looks disappointing compared to the effort put into it after you have owned it for a while.
it is similar to how a product photo of a device can look really cool and badass, but when you buy it and open the box, it looks more cheesy and toy like. While it can improve the look, it generally is not worth the work.
e.g.,
looks interesting with good lighting.
http://i.imgur.com/bI4evVI.jpg