Stock NAD 3020i Upgrade path.

I still have, and use daily, my 3020i but Im getting the upgrade bug using my source is a SACD player.

After some lurking and research I'm looking to tack the upgrade but I'd appreciate knowing where to start, or at least which projects to tackle for the for the greatest benefit.

Likewise I'd be all to pleased to learn what upgrades would be a waste of time!

I'm lookng at the following individual projects:

Pre-amp regulated power supply diodes

Power-amp unreglated power supply diodes

Signal capacitors

Signal resistors

Modify circuit design to eliminate tone and/or balance controls

TIA for any help I can get.