They are spot welded from the factory, not tig or mig. I've seen at least 10 crx's with swaps and cracked mig welds. The axle geometry is not good on weld in's nor was it even good from the factory on jdm sir's that is the why Honda changed up the front suspension setups in 92 for better axle geometry.I've also noticed that way more crx's with weld in's have axle breaking issues than swaps with a good engineered mount kit. I've done over 10 swaps in 4th gen civics and 2nd gen crxs and have done them both ways. A good mount kit like Hasport is much better than weld in, and I speak from experience and do know what I'm talking about.

About mig vs tig in my experiences tig is much better/stronger type of weld, we only used tig welds to tube frame our SAE Baja car and after several wrecks all the welds held up even though the frame bent to shit. If mig was stronger then why are all decent tubular turbo manifolds made with tig welds? Because mig welds crack much easier under torsion.

Now about the weld in jobs on crx's and such I'm not saying I'd be all for it if it was tig'd or spot welded, I'm pretty much against the idea as a whole. To each his own if you want to weld in your motor, go for it.