wow that's great, these are overall very good cars, after I got my first one I was hooked so I got another. My gf and I used these as commuter errand cars until hers was totaled while parked. I have several other cars but didn't want to give this one up so I am just about finished doing a major job on it. With only 25K on the clock you've got a lot of life left in it, mine is at 180k so it's not surprising the original timing chain guide disintegrated and caused a major problem.
This is really the only issue to be wary of, the original guide is all plastic which will start to break up after so many miles, typically the chain starts to rattle progressively louder over many months. This is a sign of the guide starting to wear/break. I've read that if you are diligent about oil changes that you may not have any trouble even with the stock plastic guide. You're at an advantage because you're starting with a super low mileage engine and can take advantage of what others have already experienced.
As far as intake manifold clogging I didn't have much on mine, sure there was residue but nothing I would describe as clogged runners. You've got so few miles I wouldn't be concerned but I would use intake/injector cleaner (you can get Techron at Costco cheap) added to the tank every so often, once every couple months or depending on how many miles you drive. The most residue I found was in the EGR passage which requires a bit of work to get to so it's not something you do every so often without having good reason, it's not a common maintenance item.
When you change your air filter go ahead and clean the throttle body valve and the seat, you'll see it gets dirty. At this point you've got a long way to go so keep up on maintenance and enjoy it. Oh and if you start to get an exhaust leak at the exhaust manifold, just make sure not to overtighten the nuts when putting the manifold back, you will snap the studs. Return to the forum for more details if you ever have to do this.
Enjoy the ride......
ps if you want to improve handling on a budget, look for a set of stock 15" wheels/tires from a 240SX, as long as the tires are a good model you'll be quite pleased with the results.
