StarRoms has been around for a few weeks now and has varying opinions in the MAME world. Personally, I'm 100% for it. Any opportunity that I can get to legalise x or y, I take.
Yesterday, StarRoms donated $500 to the MameWorld dumping fund, which if you don't already know is a fund set up to buy new PCBs AND/OR hardware for preserving. Link
As for the showing that you bought the ROM, when you buy a ROM, you have the option of requesting a receipt to be sent to you via e-mail.