You can probably start with 4 Wheel Parts on South Tacoma Way, and go from there. There are a number of aftermarket types of shops for vehicles, depending on what kind of work you're looking for. There's a little shop almost downtown that can rebuild leaf springs, or set you up with various custom options. There are all sorts of truck accessory stores, but don't necessarily cater to 4x4's specifically. For tires, that's pretty much player's choice, but I've always had good luck with Les Schwab. There are a number of their stores in the area, and they have the Toyo M/T's, which are pretty pricey, but they appear to be a really well built tire. Low road noise, and still a really aggressive tread design. Their shops usually have a bunch of 4x4 freaks, so they can help point you in the right direction if they can't do the work themselves. They're a standard tire shop that can do alignment, suspension, brakes, etc., but they can also get you set up with some aftermarket stuff too. Best indicator is to drive behind each Les Schwab you come across, and see how many employees trucks are 4x4's. That'll point you in the right direction.

For engine work, that again depends on type of engine (diesel/gas/nuclear power plant/etc.), but I'm sure there are plenty of folks that can help you out. If the guys at 4 Wheel Parts can't do the work, I'm sure they can point you to who can. There's a classic car sales place just north of 4 Wheel on South Tacoma Way, and while they may not deal with 4x4's specifically, they do carry a lot of performance parts in their shop as well. Most of it is for older performance engines (carb versus EFI), but they could be a resource as well. I can't remember their name, but they're on South Tacoma Way, and I think they're less than a mile north of 4 Wheel.

I used to deal with a truck accessory shop down in Lacey, Washington, which is about 30 miles south of Tacoma. It's called Prestige Truck Accessories, and theyr'e on Martin Way. They do hitches, winches, tool boxes, canopies, nerf bars, and all sorts of other accessories, so they might be able to help as well.

Off the top of my head that's about it for off the shelf locations that I can remember. Hope it helps.