In regards to Techron, it is produced by Chevron, so if there is a Chevron station near you you could try there first. We sell it at the dealership I work at under the BMW label (BMW fuel additive, same stuff). Otherwise I don't know who else carries it. The seat trim you're probably better off buying new, probably ditto on the fusebox lid. You could try "partsshop here first" if you want to, I don't care, what are they going to do FIRE ME!!!!??? Fuse box lid it a hell of a pain to install, just so ya know. It's probably missing for this reason. Sure it ain't in the trunk? Don't know why you think you may drop the tank, it's in the trunk also, you pulling it out? I wouldn't bother, just drain it by removing the supply hose off underneath. How full of gas is it? Maybe you can just dilute it if there is less than a 1/4 tank or so. If there was pressure in the tank it's usually an indication of low fuel level. In regards to where you buy your stuff, there is something to be said for at least occasionally supporting your local MB dealer. Everyone thinks the dealers prices are so high, not realizing how much has to be invested in the dealership in terms of training and tools and so forth to keep the dealership current all the new stuff. Just food for thought for ya there.....Gilly