Is it normal though? I'm not experienced enough to judge the quality of the finish. But the gunmetal parts are super durable, the blood red feels tough too but the matte black...it feels rough on touch and it feels like it's very weak. Very prone to scratches.

Does top coating the parts mitigates this problem?
Surprisingly the inner frame (gunmetal) is super durable. Only the matte black is very prone to scratches. Does top coating the parts before putting them back

If you use your thumb gently/litter force rub the surface did your hand get colored? If yes that mean the surface is painted with too dry during airbrush (high pressure) so you might want to try airbrush it till look misty wet like suggested earlier. For movable joint between parts like Shauno suggest can sand down to make some gap between avoid direct contact.

Edit: Matte surface suppose to feel bit rough compare to gloss.

i have transparent & white based decal. but for gradient color it failed to print out.
Bsides normal printer quality is not HD.
I want to reprint F1 Mp4 13 decal.

If anything, top coat makes things worse, because you're adding another layer and making the area thicker. anyway, try sanding down. there is no visible difference on how the kit looks. if it doesn't work. there is not issue

It doesn't strip away that easily though. Just that if painted parts came in contact with another painted part, the black will have scratch mark.

I'll see what I can do, thanks!
Can you tell me where you buy the decal papers? I might wanna try printing my own decals also. But not gradient la.
Ah, too bad all my parts are already painted.  I thought the top coat will provide a wee bit of protection... 

Actually top coat does help prevent scratch. My kit after finish paint I forgot to top coat and after fiddling the kit for a while got some minor scratch on it.

Also cut your finger nail. It is more likely scratch on surface

Feel I need to clarify a bit. As poster above mention, top coat WILL provide protection. However, if your paints are getting scratched off because of rubbing between parts, it won't help much.

Even if you've painted you can still go back and sand down the insides a bit. Not the end of the world..

OMG... I'm so unwilling to buy and build PG red frame all over again.... 

PG Red Frame - Kai

I have to say the PG Kai is so much better looking

very nice indeed,but seems like cant stand on its own without any support.

Actually if you have PG kits, you know most of them cannot stand on its own due to their backpack or accesories

well without those extra accessory i think is justify with a chrome V fin. Still i think Bandai is milking fan out of variable unicorn . So next release P bandai again with Armed Armor DE on unicorn become ver  Bande Dessinee ?

Unfortunately Bandai already make that. The armed armor DE add-on bundled with manga volume IIRC

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For today news, today is 30th years of CCA anniversary.
Bandai teasing us with new design frame which everyone guess correctly. The MG Jegan.

yeah that true however they did it to sinanju bazooka launcher and then they came out another version with bazooka included too. 

Forgot about that. But Sinanju included bazooka is OVA version. He does use that in anime too. Unlike armed armor DE which Unicorn Bande Dessinee only use. I doubt we ever get Bande Dessinee promoted in MG again.