My understanding:
The larger wheel such as a 19-20 will change ur gear ratios in relationship to speed. Where once the manual switched from 2nd to 3rd at ~70mph now it will do i closer to 80mph. Thtas not a good thing considering the low power and torque of our 6thgens. The car will indeed be a slow POS with blinging rims. For example I see a tremendouse differeance in accelaration between my 16in autox rims and around town 18's. Think of it as the front gears on ur bike. The larger u make that gear the harder it is to start out but in the end u end up having a higher top speed. So if ur the "2nd gear" peddling ur accord on the 20's u will have a rought time getting up the rpms but eventually u will owne the regular 2nd gear in speed. This is bad news since there is a perfectly fine 3rd and 4th gear waiting to be used

Bottom line u don't have enough power to use 20's and 19's unless u want to roll around the block wit ur g's