Physically, a 4" speaker will fit in it's place. Any 4" speaker is better sounding then the the 3.5" speakers. In this case, bigger is better for the sound reproduction. If you are going to use 4" speakers, just make sure the original hole opening underneath the dash can clear the speaker's surround mount and the dash's edge is not touching the speaker. You can always open the dash's diameter a little bit wider if you need to to do so with a Dremel tool. Do use goggles for eye protection and long sleeves if you don't want to be "itching" when removing the dash's material. Also do check any speaker used that the "protruding tweeter" is not touching the dash's underside, if it does, used spacers, otherwise it will not mount correctly and or can crush or deform the tweeter. Also to get better sound out of any speakers installed, you would have to encase the speakers as to make an box enclosure -- a "speaker box." A box enclosure is not necessary but the boxed enclosure will help create some bass tones and add warmth to the sound, other wise it will sound "tinny" and maybe shrill -- As an open speaker. On the glove compartment side it will be tricky to make a box, because of the glove compartment is in the way directly under the right speaker..... This where you will have to be creative with your designs and your abilities with materials as to make the enclosure with the same cubic volume enclosure as the left speaker. Kayo Ong #5508 Lic 9D NY ------------------------------------ To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: mailto:dmcnews-digest@xxxxxxxxxxxxxxx mailto:dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/