Which radiator to choose?
 

As I'm gradually improving my driving skills, I'm driving more of the lap at WOT which is in turn raising coolant temps. As background, it's a MY00 with stock drivetrain, Ohlins and upgraded brakes running 255 square tires. Oil is cooled with a SBG oil cooler. I live in Colorado so most tracks are at 5k elevation and above with corresponding thinner air. When I first started tracking the S2000 I watched coolant temps and they rarely went over 215. Lately I'm seeing 225 consistently and occasional peaks into the 230s. I do about 15 days a year so am thinking it might be a good idea to upgrade the radiator - I realize 230s isn't a problem by itself, but I'd rather make a small investment for overall longevity as well as not have to think about it anymore. FYI, I don't want to change fans unless the radiator by itself doesn't make a big enough difference.

From what I can tell searching here, the Mishimoto and Koyo Hyper V are the two to consider. Anecdotally I think the Koyo has less people complaining about it, so seems like it might be the better choice. It's probably a bit cheaper too, but that's really not a big issue.

So my questions are:

1. Are there any significant differences between the two?
2. What about installation? Any mods needed due to the extra thickness? I don't think so, but it's not really clear from the pictures I've found.
3. How much of a temperature drop should I expect?
4. Anything else to consider?

I've been running the older Koyo since 2010. Great fitment, quality, and temp control.
Project S2000 Part 5: Keeping it From Overheating

The hottest weather I've tracked in has been 102F and the coolant temp doesn't budge from 190F thermostat setting.
Project S2000: Part 19 - Ram Air!!! Plus Hot Air Testing!

Mr. Sideways x SBG High Performance Radiator - SakeBomb Garage LLC

I'm running one of the original runs that Ian did on his own before selling the design/rights to SakeBomb. It's an awesome radiator. I can pound on my car all day long in 100F summer weather no problem.

The Mr. Sideways radiator is worth every penny.

I am running a Koyo, and while I have not had a single issue and it keeps my coolant temps in check, if I had to do it again I would have gone with a Mr.Sideways/SakeBomb radiator.

The Mr. Sideways rad looks like a nice piece, but given it's more than two times the price of the Toyo, I wonder if it's worth it given I plan to leave the engine stock.

A few questions about it that are not clear from the SBG website:

1. What about the lower rad hose? It's moved to the other side so I'm assuming the stock hose cannot be used. Is that what their Samco hose at $175 is for?
2. Can the stock fans still be used? For a stock motor I don't see any clearance issues with them and doubt their low profile fans would pull any more air vs. the OEMs.

All that said, I'm still leaning toward the Koyo. I really only want/need to take the temps down about 10 - 15 deg F and the MotoIQ test suggests rather conservatively that this is likely. I found a site with rad and cap for $275 delivered that's tempting...

Once the temps are over the thermostat a lower one wont help. Just do the rad and leave the oem thermostat in. With my Koyo my car ran off the thermostat on track. never saw over 187* even in 100* FL Summer.

Note that Mishimoto has 2 radiators, one with a thicker core. The Koyo is the Hyper-V designed for clearance issue, that is, its 36mm. CSF has regular radiators and a thicker dual pass (like the Mr. Sideways) sold through Rockstar Garage. It is also described on this CSF page. CSF has a huge business with US-built radiators and charge coolers for a lot of high performance cars. However, they had a horribly poorly designed S2000 radiator with internal oil cooler sold exclusively by Jackson Racing that had to be recalled.

On paper, for a hot summer day on a track with 60+% WOT, the thicker Mishmoto or the double-pass Rockstar CSF or Sakebomb Mr. Sideways are probably the way to go.