Having an 03 C&R license will not change anything about how you buy or sell non-C&R firearms. They still have to go through an 01 FFL.
Most FFL's around here charge $20 -$30 per firearm transfer. I've only had my C&R for a year, and it paid for itself on the second C&R eligible transaction. You might be audited once a year, or you might go for twenty years and not ever be audited. I've had my C&R for a year and haven't been audited yet. I've never heard of any C&R audit being a problem anyway, unless you aren't keeping your books properly, (keeping a C&R log is easy, BTW.) All you are required to record in your bound book are the C&R transactions that took place while your license was in effect. That's all the BATFE is interested in.