A pair of crossover and tweeter. The tweeter should not be more than 1.5in. Would be nice if it has a tweeter attenuation with a warm sound. Around $40 budget.
I have a pair of kicker r19 tweeters with crossovers from an rs4 set. Not sure about the sound as ive never used them but they are highly regarded tweeters from the late 90s. i could do 50 shipped for the tweets and crossovers