Saving Tax under Sec 80C & Escaping Tax Audit

hi,

I am proprietor of a firm with an annual turnover/sales of Rs. 40 lacs. As per section 44 AD for AY 2011-12, I am not required to get my firm audited if I declare my net profit to be 8% or more. But the profit margins in my business are only around 6%. According to the law (as I get it), if I want to declare my profit as 6%, I need to get my file audited, which would cost atleast Rs. 5000 (audit fees). Is there any way out to escape from the tax audit and also save taxes.

On top of that, I have heard that proprietary firms which are not audited can't get benefit under Sec. 80C, i.e, even if I declare my profit to be 8% on Rs. 40 lacs, I'll have to pay IT on Rs. 3,20,00 - Excempetion of Rs. 1,60,000. I am not allowed to save upto Rs. 1 lacs under Section 80C. Is this true or am I going wrong somewhere .. !!

Thanks in advance