It is crashing for me too.. I am pretty sure it is installed correctly and generally if you download a compressed file and it is not complete it will not extract gracefully.
Only other mod I have installed at the moment is the track we were going to use for the last club race.
It does not appear in the difficulty selection screen either.
There are way too many different outdated readmes hidden around this package.. and none of them are marked as being the 100% current one.(though you can guess at it, like the ones saying to install it in the stock GTC-65 GT350 folder is obviously outdated)
On the download page it says
also directory structure of the mod itself)
---Will not overwrite original GT350 files, as these will show as 'Shelby Boss 302' in
GTC-TC-76 class---.
but in what /looks/ to be the latest crocko05 readme is says this:
---Will not overwrite original GT350 files, as these will show as 'Shelby Boss 302' in
GTC-TC-65 class---.
I am sorry but I have to say that this mod was handled terribly. Once you get it working it may be great, but the documentation and trying to get it to work is terrible.
*Edit
Interestingly there is a post in the comments on page two(14th Sep 2011) where someone is asking why he needs a forza disc... That is common with mods that are ripped from forza and those come packed in actual installers...... I am thinking it is very likely that this files was buggered with and then re-uploaded and something was broken in the process. There is someone from 29th Nov 2009 who said he was crashing amid everyone else with positive comments. So idk what is going on.
*Edit
Oh, and I did just redownload it, I poked the name of the file into google and found a copy uploaded to mediafire.. still nogo.
To sum up the symptoms it does not appear in the showroom or the difficulty selection screen and GTL crashes when you try to use it. But it is listed in the GTC-GT-76 car list.