Im thinking of renting out my primary which will cashflow $650 (no management fee, self manage) because of low interest rate i got it for 2% which still has 2 years before rates renew. 

It looks like a database for deed transfers.

@Sebastian SoveroThere are 3 main parts to a seller financing deal: down payment, interest rate, and price (4th would be the term).

Nobody knows lead conversion rates, except maybe the company who is converting them. 

My questions are around taxation - i have read that if the rental is not associated with a us trade or business, then the gross income from the rental is taxed at 30%, however if associated with a us trade or business, then graduated rates apply, as well as the net is taxed and not the gross.

I live in NJ, and it has a very high cost of living and with the current rate of interest, makes it a very pricey market so to say, and not that investment real estate friendly.

I keep wondering about insurance, vacancy rates, if tenant selection is a bigger/ different factor, terms of the tenancy and differences in opex and capex? 

That's true of every market now, I suppose, with interest rates and supply problems, until either prices go down or rents go up.

Right now the mortgage rates I'm being quoted for a 20% down DSCR is 7.75%. 

With high interest rates, we'd be looking at around $3800 PITI.