3-2-1 swap a s197 or gen 2 s550?

I am considering buying a gen 2 2015-2017 mustang gt 6spd auto. However I recently bought a 2011 mustang gt and my problem is how much boost the car will reliably handle. I know that the gen 1s can handle 600whp and gen 2s can handle 800whp. Yes I want the extra horsepower as i think itd be cool to run sub 10 1/4 miles and im kind of doubting the gen 1 can run a sub 10 on a stock block but also i think i would prefer the handling that comes with the s550s. I dont care as much about the interior(yes its cool but not everything) but i definitely do prefer the s197 body style over s550. However It’d basically be a waste of around 7k if i were too trade in my current s197 and buy a s550 considering taxes and warranty. Alternatively I could do a 3-2-1 swap, however im worried about the reliability and cost. My questions are should i buy a s550 over doing a 3-2-1 swap? Are 3-2-1 swaps reliable? How much am I likely too spend on a 3-2-1 swap?