Suspension advice

Best bang for buck in my opinion would be a set of BC coilovers, only upgrading the front swaybar can cause some issues with under steer. Bush kit is a good start I would also recommend checking all ball joints and upgrading to the urethane engine mounts. I have also installed the Megan racing adjustable front tension rods and adjustable rear trailing arms. My sw20 feels really good to drive very responsive feels good on the track and still well behaved on the road.

Thanks for the suggestions.
I never thought about upgrading the engine mounts. I honestly had no idea what that would do until I have done a bit of research on that a few minutes ago. It seems like peoples either love or hate them though. I am thinking about getting them. I do have quite a few things rattling in the cabin already though, so I should probably try to fix these first or it's going to drive me crazy with stiffer mounts...
 
Not super convinced about the coilovers tbh, I had some (sleeve type) on my previous car and I didn't care all that much for them. Wouldn't lowering springs work the same way anyway (other than not allowing you to go as low and having as much control, but honestly, after finding a good height, I am not sure why I'd ever want to mess about with the height again)?
 
Cheers, I will also have a look at the ball joints and tie rod ends to see if they need to be replaced. And I guess I probably shouldn't just upgrade my front sway bar after all with my current setup?

It all comes down to your budget. The BC is a great base line coilover but for $1500-$2000, I would highly recommend the Spax coilover. The support with set up and ongoing development is very good.
I think the coilover allows for easy fitment of different spring rates for tuning the car. Also allows you to tune the rake of the car to help with set up.
Go with the bush upgrade but do not replace a OEM spherical bearing with a Nolethane bush or the likes. Big step backwards.
I would not bother with the swaybars. Just get the spring rate correct and you should be ok with standard bars.
The adjustable end links are for resetting the swaybar after lowering the car. If you don't go too low you will be ok.
Spending money on eliminating bump steer and improving roll centres is a far better way to spend money instead of sway bars. Infact, I would start here if I had my time again.
If you are going to the track, get some 17's or 16's. 18's are just too big and heavy effecting braking, accelerating and cornering.  
 

Thanks for the feedback :)
Still not super sold on the coilovers, even though everyone seem to be loving them. If they weren't that expensive, I would probably give them another go.
I bought the kirkausaurus engine mount that someone recommended (mostly because they were cheap and are easy to revert back to stock), and I will probably get the bushings if I can get someone to install them for a good price. I also mostly gave up on upgrading the sway bars, at least for now.
And yeah, I want to get smaller rims, probably 17" rims. I just need to find a good deal on a 17" rims and tyres package.

So, I went to a suspension shop today since my car was getting really bouncy and apparently I need 3 new lower ball joints, new rear sway bar bushings and new shocks all around ;/
I am looking at my options. Right now I am thinking either BR BC coilovers ($1300) + 3 ball joints from amayama ($120 + shipping)
OR
4 koni inserts + 4 ball joints from Two'R'us ($700 USD + $250 USD shipping).
 
Coilovers sound more exciting BUT I doesn't look like they would fit with the rims I just bought a few weeks ago ;/
17"x7" +45 (no tyres on them yet); so it looks like I don't really have much of a choice unless I buy new rims, do I?
Thoughts?

hey alex I am getting a price on konis for my volvo from one of our local shops ill get a price for the mr2 stuff too.

Top performance (Aussie Koni dealer) in Victoria quoted me $550 a pair. eBay was around $900AUD shipped for me from US. Fast shipping + support locals vs cheaper although it only took about 2 weeks, not bad. Prices are circa December 2013
 
My experience with Koni yellows + the hardest aftermarket springs known so far (RSR Race) - great for daily and spirited drives, stiffer than bone stock by perhaps 25% guesstimate. If you are chasing lap times tho I would go coilover in a heart beat. Otherwise the aftermarket springs and the shocks off the shelf are too soft for track days imo.
 
NB - See the excel file under FAQs bottom right of the website for spring rate compilation