In the car setup screen (the screen after you select which car you want) there is a list of skins on the left, at the bottom of this list there should be a button called "New colours" click that and it will bring up a list of your newly downloaded or created skins then click the one you want
I made this one Click which is pretty similar to the your requesting, It should be pretty easy to convert/edit it to the one you posted, will have ago when i get chance
Edit: not so sure about the dirt layer, never tried one before but will have ago one.
could be packet loss, try pingtest.net, this will show your line quality and packet loss. had a similar problem with BT at peak time a while ago. do you have a capped or limited connection?
what Bean0 said, also get him to check he doesn't have another skin saved as the same name as your new one, if he does he will see the one he has saved as all lfs checks is skin file names before downloading any missing/new ones.
Edit : sorry kifp typed this as you posted, to answer your question you must upload it to lfsworld or noone else will see it
The reason I ask is that you pasted the roof backwards as you can see the start of the rear wing at the top of the windscreen (the chopped sti logos) also the yellow stripe on the roof curves the wrong way as to what it should. Also if your going to use Squales detail kit don't chop his credits off the skin file.
The only reason I post this is because i made this skin not so long ago from scratch Here and it caught my attention
I haven't read through the whole of this thread but why have ago at Jaz, I see his original point its looks like you put no effort into creating a request so skinners will probably ignore it knowing that the skin will probably never get used. You could at least give people a rough idea of what you want i.e what colours you want, what sponsors and maybe even a description of what style you want. If it's for a team then maybe even post up a bit of info about the team to show your serious not just a team that will disappear next week.
He has created many high quality skins for the community along with a full guide of how to compensate for logo stretching. The only way people improve is by getting constructive criticism from more experienced skinners. If you just say "great job" when there are clearly errors then the person making it will never learn/improve.