With any handling problem the first thing to ask is under what condition does it understeer , turn in or exit. are you turning in under power or do you trial brake into the apex. Does the understeer build progerssively with the application of power?
I do not Know your driving experiance level but I will assume you know the basics so here are a couple of things to check
If the new shocks are softer than the car is likely to understeer more than it did before.if the shocks are adjustable you could try stiffening them up. Be advised if you crank in to much rebound damping the car will oversteer on entry , the rear end will jack down in long bumpy sweepers and cuase some really goofy handling. Also check the tire pressure - air is a spring and what ever end of the car is sprung more stiffly will break lose first , not to mention if you've over inflated the front tires they will be crowned and have less rubber on the road. I would check the alignment , to much toe-in will definetly cuase terminal understeer. I run the H145 LSD in my racer and have never had a problem with it bieng to tight , over course a binding LSD would make your car undesteer same as a locked diff.
I would do the basics - check the tire pressure and alignment and make sure no parts are worn - LSD suspension etc.
On a Final note if you don't trail the brakes into corners try the technique in an parking lot before you put it to use on the road as it will make the car oversteer. ( I'd hate to hear you backed your car into a tree!!!)

Tom Grossmann