A guy down the street is trying to do a budget build, and I told him changing the stock ls1 disc for a semi-metallic or sintered iron would probably increase holding capacity significantly without having to spend $1000 on an aftermarket setup. Does anyone have experience with just changing to a grabbier disc with the stock ls1 flywheel and PP?

yes, a puc style ceramic compound disc on an otherwise stock PP/FW will increase holding but decrease street manners as more aggressive disc compounds typically chatter on engagement unless rpm and release are perfect. High RPM clutch dumps are their good spot if that is the primary use intent

I am aware of that (and you forgot squealing noise), but I was hoping somebody had experience with how much extra holding capacity a more aggressive disc might have. And I am also aware that metallic discs eat flywheel and PP surfaces much quicker than organic discs.

My $.02 after running SPEC ceramic puc, ZOOM Kevlar puc, Competition Clutch full face organic with higher pressure PP, Stock clutch (Valeo) is the alterative single disc clutch material did hold and crab better than stock but all had short lives (maybe a year) with weekend drag race use and aggressive street runs behind a mild 383. Hard to say a % more of how well they held, maybe 20% measured by Butt-o-meter

Switching to a twin disc clutch was the answer and what I should have done initially. Takes a beating and does not blink. It is full face organic discs, McLeod. Their ceramic puc disc would hold even more but have a narrow window on clutch chatter on engagement but better suited for frequent drag race use

I still have the OZ700 single disc Textralia in my GTO that I put in it about 20,000 miles ago. When it eventually goes out I will definitely go to a multi disc clutch. The guy down the street just put in a new stock setup a few miles before riding in my car and deciding to turbo his. We are just discussing ways he can get around buying a whole new clutch package for the time being, because I know from experience that the full stock setup will be slipping even at just 5lbs of boost when the turbo goes on.

I like my Diamond stage 2 clutch from Texas Drivetrain Performance. Not too aggressive for street driving.