You can use a traditional style cooler as well. But the smart cooler built into the cart is pretty cool. I almost wasn't gonna get it either, but I got talked into it and I'm glad I did! It's just a much nicer setup overall.
Accessories for the TIG? Definitely get the 25ft hoses. It's up to you if you want the 300A torch, or the 350A torch. The 300A torch uses 9/20 consumables, where as the 350A torch uses 17/26/18 consumables. You can also check with TIGControl.com if their TIG Button works for the 313. I think it will because I worked with them to figure it all out for the 400. It was tricky but in the end we got it to work. If you plan to weld stainless and only want to use 1 tank to both weld and purge, you can upgrade the flowmeter to their dual-outlet flowmeter with independently adjustable flow-rates.
Now for the MIG, the slider is indispensable in my opinion. If you don't have it, it's like trying to TIG without a footpedal (or another form of remote control): possible yes, but very limiting. Even though millions of miles of welds have been done with both TIG and MIG without variable remote amperage control, there's no denying a footpedal is a great form of control for TIG's, so the slider plays the same role for MIG. Consider getting the high-heat Copper-Chrome-Zirconium (CuCrZr) tips, as they last lot longer and can take the heat for pulsed-MIG welding. They also have tons of different torch options. I know a couple guys who run 20-25ft MIG guns on the PP300 with dual shield wire (gas shielded flux core). Those knurled rollers grip very well! There's also water-cooled MIG guns for aluminum, spool guns, push-pull-guns. There's just a ton of upgrade for the PP300. I bought the sets of geared-rollers for aluminum so all 4 drive the wire into a water-cooled 10ft gun. Works awesome. Makes for excellent feedability. But yea just call them up and ask them to tell you everything that is available and I'm sure they'll walk you through it all. In short yes, they can customize it how ever you want. You pick and choose, and they update the invoice, lol. Man, gotta love those invoices!
Oh and you can also get a wireless pedal for the TIG if you want to. It works pretty pretty good!
