Before you do anything you need to decide what you want to do with the car, what you want from it, your budget and what you can do yourself.
SOA doesnt really increase flex for the same bump clearances, it increases clearances tyre to body/chassis, under diff etc allowing potentially more flex and trail clearance.
Myself I was on a really tight budget and my car is a daily driver running upto 35''-36'' tyres offroad. I chose to remain with SPUA but still got excellent results with the front end, the rear worked ok but is limited by tyre to inner guard clearance, even with a 60 series rear axle. Modified front shock mounts are a must.
On this car I did a RUF (rear springs up front) combined with a 2'' extended shackle.