Unless the radiator is leaking or it and the cooling system fails a pressure test there is no need to replace until it does. Catastrophic failure is highly unlikely. It will just start leaking one day. If it is the original radiator then someone was good about proper factory cooling system care all these years.
“Cooling System Problems” often lie elsewhere, like a radiator fan switch or thermostat – or worse.
It has been my personal and professional experience that aluminum / plastic radiators last a very long time and are more than suitable for all but the most highly modified motors for the street or track. Other than your budget and desires, there is no real wrong answer here. Performance all metal radiator or stock OEM? The options are yours to pick from.
Replacing radiator hoses on a turbo motor at this mileage if you change the radiator is not a bad idea. In the meantime, watch them like the radiator. Investing in a STANT brand radiator tester if your like working on cars is, in my view, a basic tool for your tool box unless you can borrow one or have access to a consumer automotive shop class at a local Junior College.
Replacing the radiator hoses after years of use is never a bad idea, radiator or not. They tend fail from the inside out when they do fail. I prefer factory clamps rather than American style clamps for hoses.
I am a Northern California native and graduated from a a Bay Area JC college in auto repair and studied with BMW-North America in my youth all in the early 1980s. It was when California implemented their first serious Smog Check Program - the “four gas” BAR84 Smog Check program.
For the last 5 years I have lived in New York. I miss salt free cars.
As long as you keep the original emission control equipment in working order, most changes to your stock motor are street legal as long as the equipment checked during the Smog Check is functioning and in place and the tail pipe readings are within the range the California Bureau of Automotive Repair (BAR) mandates.
Changing the motor to a newer motor other than what was fitted to your car is usually legal as long as the fuel and emission systems match the new motor.
For example, putting in a complete as installed from the factory 2011 Forester motor in a 1998 Forester is legal, if the fuel and emission systems are as fitted to a California market 2011 Forester. Putting a 1998 motor in a 2011 Forester without retaining all the 2011 Forester fuel and emissions control systems is not. If you are simply swapping long blocks and all the equipment and systems original to your car bolt right on to the replacement motor then you most likely are OK smog check wise. But check the CARB /BAR websites for approval information if in doubt.
In college, the game, among several, was to convert your used 1/2 ton pickup to a 3/4 ton pick up, by swapping junk yard parts like axles and the brakes etc., to be exempt from smog checks and the emission control equipment the 1/2 ton version of the truck was required to have without actually replacing your already paid for and modified 1/2 pick up with a stock 3/4 ton pickup. It never made sense to me.
Unless the law has changed in the last 6 years, once a car is more than 25 years old (26 model years) this is no longer really an issue as smog checks are no longer required for cars that old or older. Having said that, double check. O2 sensors have been required on cars sold in California since 1981, so original emission control equipment is still required to keep a car "as built" legal in most cases.
As for performance parts, here again, unless the laws have changed, they must be CARB approved “for street use”. Something that has never really been an issue for, say, modifying a 1967 VW Beetle even when new, but has always been an issue for, say, a 1985 VW Golf GTI, for example.
There are so many things to think about with modern motor swaps, as opposed to simply rebuilding a motor with performance improvements in mind, that swapping motors, in my view, is more a labor of love than is really practical. If we were in Germany, then such “street legal” engine swaps become much more feasible.
Modifying a stock motor in the car you already have carries its own sets of considerations. My hot rodding days are long over and for years now I have preferred cars that perform well at interstate speeds and above with good drivability and economy. I have been a VW / Audi owner since I was a teen and, with few exceptions where mild modifications proved useful, stock motors met my needs, especially if they where diesels.
The 2010 Forester, that brought me to this site, I got for my oldest daughter as her first job post college daily driver. The last year of the EJ motor, I picked it largely because, though the FB motor is more refined and slightly more economical in fuel use with improved emissions, the slightly higher maintenance, due to the external timing belt, normally aspirated EJ motor is the simpler motor to service in my driveway or where ever her first job as a wildlife biologist takes her.
So my needs are a simple, easy to maintain, daily driver that, given the rather low miles to date, should serve her well. Your stock motor has apparently performed and driven well for many miles. Major changes to get “more performance” most likely will change that balance. I have seen many an owner, even though I sold them the performance parts they so wanted, change their cars from maybe a bit of a boring daily driver into a “fast car” that in turn became an unreliable, poor to drive, daily driver.
When done well, performance upgrades and modifications take not only well researched choices, but they take money too. As we quickly learned in college, “Speed costs money. How fast do you want to go?”