[BimmerAg]

First of all, welcome! I'll try to address your points one-by-one the best I can:

Originally Posted by asiflicious

My issue is not grip or traction so I dont think I'm in need of new tires at the moment, especially since the oem ones I have on right now are pretty much brand new. I will eventually get better tires, but not until these ones are done for.

The OEM runflats are known for being loud, expensive, not having great grip, and having a rough ride. Most people recommend replacing them as soon as you can, but I totally understand wanting to get the most out of your current tires first, and I think you can achieve the handling you want with other modifications.

Originally Posted by asiflicious

I'm a bit skeptical about coilovers because I'm not looking to slam my car, I'm looking to improve the performance but it seems everyone talks about coilovers in terms of aesthetics and not performance. I'm not opposed to coilovers if they will make a noticable improvement to the handling of the car, but I do not want to spend over a thousand dollars just for a ride height drop. So will coilovers help with performance or not?

In some other car scenes, coilovers are more of an aesthetic mod. Luckily from what I've seen on this forum, most members seem to be more focused on handling and performance and coilovers will 100% provide that if you get a QUALITY set. Blistein, Ohlins, Koni, KW, etc are all high quality sets, but can be closer to two thousand dollars. If you don't do very much track driving, then I'd recommend a spring and shock upgrade instead, preferably a matched set like this: https://www.turnermotorsport.com/p-1...nsion-package/
Koni also makes a kit with their yellow sport shocks and the same eibach springs. Be advised, both these kits will results in about a 1" drop. If you're not looking for that much of a drop, the BMW performance suspension (maybe 1/2" drop) is also very highly regarded, although it is more expensive: https://www.turnermotorsport.com/p-5...front-swaybar/

Originally Posted by asiflicious

I understand the benefits of an LSD, but it seems the general consensus is that it's not worth the money on a street car.

For a street car, LSD is definitely lower on the list, especially because of the high cost.

Originally Posted by asiflicious

As far as the M3 subframe bushings go, I'm ashamed to admit that I do not know what subframe bushings are, what they do, or how M3 bushings will improve handling. Can any of you shed some light on this?

The rear subframe basically holds all the rear drivetrain parts. To connect the subframe to the main frame of the car, there are a few bolts with rubber bushings around them. These bushings help isolate some of the bumps and harshness from the road, but the stock bushings are very soft and can deflect under high loads, which makes the rear end feel unstable. The M3 bushing, is made of a stiffer rubber that doesn't deflect as much, and it gives the rear a much more planted feel, although it can come at the expense of slightly more NVH transmitted into the cabin. If you can do the work yourself, people say this is one of the best bang-for-the-buck upgrades you can do for your car's handling. also, I'd recommend using a 2-piece bushing for easier installation. Like this: http://www.whiteline.com.au/product_...=KDT917&sq=773

The M3/1M front control arms will help fight understeer by adding about .75° of negative camber. They also include stiffer bushings than the stock arms that will slightly firm up the front suspension.

Originally Posted by asiflicious

I'm just trying to make the car feel more planted and less rolly or floaty. Any advice on where I should begin to achieve this goal? I'm really looking for the mods that are the most bang for your buck and make the biggest difference. As much as I would love to go all out and put in everything, I can't afford to do all that. So if I could get like a top 3 mods list and a little explanation of what exactly those mods do and how they improve the handling characteristics and a rough estimate of how much I should expect to pay to have said mods installed, I would greatly appreciate it. Thank you

Obviously, what mods are best will depend on what you want to do with the car, but it sounds to me like you want a better handling road car, not a track/autocross car. Based on that, I'd recommend the following top 3 mods:
1: Rear subframe bushing - one of the least expensive mods in your list (if you can do it yourself) and will really help plant the rear of the car
2: Spring/shock upgrade - This will make the biggest difference in how your car handles so make sure you go for a high quality kit. Stiffer springs will reduce body roll and firmer shocks will help get rid of the floaty feeling you're describing
3: Either new tires or M3 sway bar - With firmer suspension, you may feel like your car's ride has gotten rougher than you like. Luckily, non-runflat tires feel softer than the stock runflats and should get you back to a stock-like ride quality. If you don't mind the firmer ride, then the M3 sway bar is pretty cheap and will also reduce body roll.

Hope that helps! I'm also new to the 1 series, but I've been doing a lot of research lately and have pretty much decided to start with the same mods on my DD/weekend racer