Topic

Well often I read about getting the shell or the subframes seam welded,

I don't really know why is people so concerned (I know that they should add rigidity) But is it worth it?

And why?

What is the difference to the OEM welds?

As you say, it is for strength.

A normal subframe or shell is spot welded at worst or partially welded at best, i.e. 1" welds every 3 - 6".

By seam welding you are using a more continuous weld, which is better for torsional stresses etc.

Have a look here.

http://www.mwstewart.co.uk/articles/mk3xr2iseamweld/

I've seam welded subframes..and engine bay..

As Clive says it makes the joints stronger... They don't do it at the factory because of costs..

Road cars that are used on race tracks are often seam welded.. We used to weld up mini's etc

Not essential.. But if you intend to go hard and fast a worthwhile mod.. In my humble opinion

Then of course you'll be wanting strut braces and body braces