you get what u pay for, take the plunge...
If your slide is damaged,( corroded, worn, plating missing or pealing off)
spend the bucks to replace it with the exact o e m part, regardless of any cost comparison to used parts. The fit up of the slide is where all of the good tune job starts.(it's a precision air valve, if you will... fit up into the carb body is critical, if it leaks air around it any tuning you do will not be reliable or consistent). As for losing parts? prior to doing any work, set up & prep the area, (clean work surface, covered with white butcher paper, good lighting, zip-lock bags or plastic bowls for the small parts, carb cleaner, some compressed air, the proper literature or manual for your carb.) Since this device controls the speed & performance & safety of your ride & you, if your not willing or able to do this correctly, find & pay a pro to do it for you. It sounds like the air filter needs replacing, the first victim of dirt getting thru is the slide, next is your engine. Good luck, Best Regards, Porkchop...