Ive just discovered that the player ID's are the user ID's that are used to view profiles in this forum. So if you want to add a user as a friend in supermechs, you can find him in the forums and add him using his user ID.
Here is how to do it:
1. Find the user in the forum(this is the hardest part since the mech name in supermechs and the username that is used to log into supermechs and the forum might be different if the player wants to) You can also add a forum user, just make sure that (s)he playes SuperMechs.

2.Click the profile link

3. the adress bar will be like :http://www.battledawn.com/forum/memberlist.php?mode=viewprofile&u=6918106 (That is the link that goes to my profile page)

4. Copy the number at the end of the adress bar, in this case: 6918106

5. Click add friend in friends section in supermechs and paste the number into the box and click on the green tick button.

6. Wait for the friend to accept or decline.

7. There is no seventh step, you're already done unless the other person has rejected your friend request.

I added you this way (and Liran too)

You'll lose money only if you use kits and replace them after the battle. Whatever if you use kits or not, you will gain a small amount of credits even if you lose your battles. So you can only run out of money by buying items(including kits).

I think what's why you write it in chinese too, but i should say i can understand such english, your translating software does a good job.