Change the oil more often, or go with full synthetic, and make sure the car does a long trip once in a while.
I feel it is worth noting that, despite the general consensus that 3k oil changes are not needed...
...I've never seen an engine on the still-common 3-4k oil change schedule experience sludging problems. At all. Even if it's turbo, even if it see wide ambient temp swings, lots of cold starts/short trips, ect. If you follow the two most common oil change schedules- most often 3k/5k at indy or chain shops, or the slightly-more-generous 3750/7500 I've seen at dealers...you're not going to ruin an engine with sludging. You will never cause ANYTHING negative, except maybe the loss of 30-45 minutes of your time and $30 for that extra oil change.
It's such cheap insurance. If a certain engine is known for sludging, oil consumption, ect, it's a smart move to keep the oil change intervals a little on the tight side.