Will this condenser work with my existing refrigerant charge?

Yes — this is a full capacity replacement. You'll recharge with the same amount your system originally held. No undercharging needed.

Do I need new O-rings and seals when I install this?

It's the right call. AC systems are sensitive to contamination. Fresh seals prevent leaks down the road and cost next to nothing compared to a second R&R.

Can I install this myself or should I go to a shop?

AC work requires a recovery machine and certification in most states — this isn't a DIY job. Take it to a qualified tech. Condenser itself bolts in fast once the system is evacuated.