Thicker Headgaskets, 2.5mm, any cons?

Im mixing a RB26 bottom end with a RB25 Neo head and the head was worked etc, quench pads removed but compression was still around 10:1+ if i used a 1.2-1.5mm HG, so i settled with a 2.5mm thick cometic headgasket.

In comparison to standard sized HGs (1.2-1.8mm) what significant cons do you get running a 2.5mm HG? Compression and quench is instantly lost, in my case i removed the pads but what else can happen? are they weaker by a big margin or something?

So far ive learned that Cooper spray breaks down the viton, so thats a no go, cometic also doesnt recommend using hylomar spray and ive read you are supposed to use the same torque on the ARP studs even when using a thicker headgasket.

Any info would be nice seeing as you guys have a lot more experience.

Cam timing is going to be affected by changing to a much bigger head gasket like that. But in your case you might anyway go custom and adjustable I reckon.

There's likely to be some effect on the quench in the engine, although this will be reduced since you've removed the quench pads. Even with the quench pads removed there would normally be some quench effect due solely to the proximity between the outside of the piston crown and the cylinder head and this is what you will lose.