First of all, even IF you reinvest all interest payments (many don't) it's closer to 3500% as he only compounds every 3 days. For many of his clients, it's only 365% interest. Borrowing USD to buy BTC is risky. Consider the following situation:
Step 1. Borrow $20k from a friend. Promise $30k
Step 2. Invest in about 3000 BTC @ $6.5
Step 3. BTC returns to $2
Step 4. Turn $6000 into $30k to pay back your friend
In an entirely plausible situation, you're 50% loan has just ballooned into a 500% loan, worse than many of the loans P@40 has already. 5% on a currency conversion is not unheard of, even for legit business. It seems very likely to me that he could easily make 1% daily on his money.
I only offer this information because I beat you to the punch so their's no way you can knock me off the list :-P.