So, the gf gifted me with a gift card to ECS Tuning for our anniversary a few weeks ago, and I realized today how close I am on an oil change, so I'm planning to use it on that. There's been a couple varieties of Liqui Moly I've been wanting to try out but I'm unsure of which to pick, or what the differences are really. Application will be a 2015 Jetta 1.8T, and will probably end up doing her 2019 Tiguan as well. Focusing on the Jetta, Im stuck between Top Tec 4200 5w30, Special Tec LL 5w30, Molygen 5w40 and Leichtlauf 5w40. Normally this car gets 5w40/0w40, however I'm considering running a 5w30 as we go into winter for something a little thinner, as we do see drops down to negative temps fairly often. Both vehicles are tuned, I'm sure any of the choices will be fine, but is there one to avoid?