Never do this and give everyone a miss asking you to do this.

I had an offer with them and they wanted me to go on a tourist visa and change it once I got there.

Yes, well, don't you pay any attention to, Another Willie, he has a track record of using wing-and-a-prayer-visas himself. The last time he went he got the sack from two jobs in his first two weeks in China, and had to accept an invitation to use a fill-in-job in USA which was to commission two new universities for them- we've all had to resort to that I suppose- all cash isn't it!

No, you should remember that you are going to China and many employers have arrangements with their local police. So grab that L visa and away you go. You tell Another Willie to sling-his-hook with his bad advice.