Hello NamelessPFG
Maybe we can get together sometime, enjoy a cool drink and share war stories. I think I may have just the thing for your "techno-gap' there...maybe quite a few options, in fact
As I'm sure you know, after the original Core2 duo/Quad CPUs, the next series of Intel CPUs was the first-gen Core i-series (i3/5/7). I have a fair selection from a couple of those platforms, to other more recent setups, including 3rd- and 4th-gen i5 and i7's. I actually don't have any 2nd-gen (2500/2600) CPUs/builds, simply because I found/bought the Z68 boards that were reasonably priced and already PCIe 3.0 capable. This way makes more sense IMHO, because buying those boards will support 3rd-gen (Ivy-Bridge) chips with a BIOS update. So, instead of Sandy Bridge, I have Ivy Bridge setups that can run recent graphics cards at full speed. (Although I do appreciate that saturation of a PCIe 2.0 x16 link is arguable, it is becoming less so). The costs overall are comparable, so it seems just as well to go with Ivy Bridge. Of course, now it is very different than when all this stuff was still current generation.
As far as capabilities, I have to admit that - until you mentioned it - I'm not familiar with BeamNG.drive. Seems very interesting, although I'm typically more a flight sim guy. But, if you can stand the shameless advertising
I can tell you a little about the way I produce the builds:
First, consider I have two 20-something sons; a "home-grown" play-testing labor force, if you will. Only one lives at home now, but the other does come for sleepovers, whereupon they play together, online, often with friends. Games like PUBG, Squad, one plays WOW, BF1, maybe Overwatch, ARK, GTA5, Fallout 4 going back a bit...I honestly have trouble keeping up
Point in all that is that these are the titles I use for "testing". Right now, PUBG is very popular - even though I may not be into it myself, the thing is, they're going to sit and play anyway, and I get free testing out of the deal *lol*. It usually goes fairly well; I don't typically give them a machine to run unless I'm already pretty sure it's going to run well.
So, the games above - mostly the newer titles - are my test criteria. Of course, we adjust graphics, etc as needed, depending on the exact build we're testing. I have a fairly good idea of the range that will run all those games at least on lower settings; I can tell you a machine like that is going to start in the $500-600 range (but that also generally includes a boot 120-240G SSD *and* a 500G-1TB HDD, 16G RAM and of course price depends heavily on the GPU). Plus, one thing I am adamantly proud about is that every machine I sell comes with a legit Windows license. Many used systems have a 'bootlegged' OS installed from one questionable source or another; I don't (and won't) do that. I also typically offer a 1 week money-back trial period, 90 days - 1 year warranty, reasonably-available on call tech support, free boot drive image restoration, free upgrade labor, and a guaranteed upgrade buy-back policy.
I even have 3-4 AMD setups, if that's your preference. As with new/retail stuff, it's more budget-friendly than Intel/Nvidia, so I have a few less expensive but still very capable all-AMD builds, too.
The GPUs I put in these systems range from R7-760 on the AMD stuff, or GTX 570 (Nvidia), to up around GTX 980s, 1060s, a R9-380...depends on what I can get my hands on for the right price
Also, I am usually very careful to not 'mismatch' the mainboard/CPUs with the GPUs. It's possible to build a high-end GPU with a low-end CPU, but it doesn't make a lot of sense. Over time, I've built a database of records for hundreds of systems/configurations with all sorts of combinations of GPUs and CPUs, and I generally build/recommend components that are evenly matched, to what the user wants to do with the machine *and* to one another. A lot of effort goes into taking all this into account as well as the 'upgrade path' if it's important to the user.
Most all the stuff as above will fall in the $500-800 range. At the high end, I don't usually sell much that approaches $1,000 (I can do it and have, just can't really afford to sit on that much cost for too long).
On the super-budget end; like you, I have some older Core2 duo/Quad stuff - even a couple of the Extreme CPUs (QX-6850, -9650). Couple of setups with those on boards that supported 2-way SLI; GTX 450's, 460's on up to 560Ti's (all picked because of being 2G RAM or less and relative performance). They are such gorgeous, wonderful machines but just can't run today's more demanding games...I have sold setups like this for as little as $200, depending. Hard to beat, IMHO, long as you're not trying to play the latest titles.
And if you want even more budget-friendly, I have machines that are more just 'productivity' machines...some with older GPUs (say ~9800GT), 4-8G RAM, CPUs like Core2 duos...these machines can go for $100, still perfectly capable for browsing, homework, email, documents and spreadsheets...even a lot of not-terribly-old games, too
Not low enough? Here's what I say to people all the time: You want a machine, from forty dollars to four thousand, built to meet your budget and reasonable performance requirements? Let me know, I can probably do it
On the liquid cooling *lol* getting my feet wet, very "punny" indeed
But, I'm afraid I'm already in it up to my eyes *lol* I've built a dozen or so like that; mine is, as well as both my sons'. Sold a couple that way...have an i7-980x here now that's up for sale with a liquid cooler in it. But, to be honest, I had reservations about liquid cooling for along time before I 'took the plunge' myself several years back. Since then I've gained some knowledge and experience, as well as confidence in the hardware. But I'm still pretty sold on 'self-contained' all-in-one systems you can buy, because they're fairly inexpensive now, usually easy to install, and very highly reliable IMHO. I honestly haven't found myself at the level of performance you've been to with custom-built plumbing
I would imagine the performance of custom-built loops is comparatively higher, but I'd also imagine a comparatively time-consuming effort. As it is, I spend far more time on these builds than there is even remotely any money in them
Anyhow - give me a shout, any time. I'd welcome the chance to discuss it with you.