do these updates make a lot of difference?they want over $210 to install them using the reload cartridges at the dealer

There r no updates that will give u any more performance(and for a 420a motor l use the phrase lightly) that r worth paying any amount of money for. The best thing u can do for that motor is replace the head gasket with the factory updated metal head gasket & be glad to not breath the oil burning on the exhaust flex pipe any more. The Neon motor in ur car is not worth spending money on with pipe dreams of having a race car. Save ur money & buy a real Mitsubishi GST or GSX with a factory turbo.