Welding Tips and Tricks

Hi Guys and Gals
My first post here so hopefully I dont make myslef sound a plonker !
I am hoping to build an EV car chassis from stainless and need some advice from all you clever guys out there. As I am in the UK I will talk about 304 and 316 and so far 304 seems to be the best choice I have been informed.
I have a few questions, based around using TIG for the small welds and MMA for the larger, unless TIG is best all round up to 3mm material?
For the TIG, which gas and do I use 304 or 316L rods?
For the MMA, which rods for general use and less chance of cracking later? Max material thickness will be 3mm. I used 'dissimilar' rods for ease of use before and so far any welds have survived... but this is on a vehicle chassis subject to corrosion and vibration etc.
Thanks for any help in advance.
stainlesspete

Use pure argon for gas and if you use a 304 base metal then you should use a 308 filler metal.

Thanks for the reply and helpful tip. I have some 316L rods, would they be ok or is 308 the best anyway?

Learning curve getting less steep

316 filler will be fine on 304 base metal, its just a little more expensive than 308.

Thanks brian, saves a bit of money using what I already have.