Best 5-pack for modding
Are there any specific HW 5-packs that is best overall to mod for racing? Or am I just better off going with lots of random cars from eBay/garage sales/craigslist/etc and hoping for the best? I want to submit a handful of cars to a race and thought a 5 pack would make it easier.
Given most races seem to require casts based on real-life cars, I guess something like the Showroom pack is preferable.
Discussion
Well, first things first: welcome to racing! There's a bunch of good people here, and LOTS of information about diecast racing. Be prepared to have several (weeks of) sleepless nights as you go through the archives. :p
As for what cars are best for racing, look at the cars with plastic bodies and metal chassis. All your weight is at the bottom of the car, which means it's going to be harder to roll. (It will not be IMPOSSIBLE to roll, but harder.) The lower the weight in the chassis, the better. Sometimes, the Color Changer cars have a chassis that can fit on another car (for instance, the Audacious hatchback: mailine car is metal body, plastic chassis, color changer is plastic body on metal chassis.) You can swap out the chassis from one to the other, making an all-metal car, thus beefing up the weight with minimal additional weight needed. As I said, lots of tips and tricks in the archives.
Wheels and axles are absolutely crucial in racing. If it doesn't spin fast, you aren't going to go fast.. Axle polishing is a thing here: nice smooth mirror-bright axles are what you want to have on your cars for the least amount of rolling resistance. The less resistance, the faster you go, right? Wheels? They are made in a standard mold, and have a seam on the tread where the wheel is popped out of the mold. That makes the car chatter loudly as it rolls, and IT KILLS SPEED. If you drag a fingernail across the tread of the wheel as you turn it, your nail will catch on the seam line where the wheel came out of the mold. Simply removing this seam line on all four wheels makes the car smoother and faster.
This gives a tiny glimpse into some of the stuff that we as racers do, but there is a LOT of information here going back over a decade. Have fun, but remember to get some sleep!
Not EXACTLY related but for the five packs or any multi-pack where the wheels can be salvaged off cars you don't want/need, such as fantasy cars, our research found that...quite a few multipack rides roll straighter/cleaner out the box than single packs. Don't know why that is though??? but that's usually the best for wheel farming as far as I see it, the multipacks...