your price is predicated on supply vs demand
the good thing is you have a 5speed. the bad no moonroof. if it's in good condition with receipts you can demand more.
don't be in a hurry to sell but also don't be unreasonable.
i'm in the market for a 99-00 p11 and to there are many people who overestimate the g20's value. i ran into some nut who wanted 17.5 for a 2000 g that had been in three accidents and higher than normal mileage.
i've seen p11s sit for months on autotrader or the reclycler because of overvaluation. the only p11 that i've seen that moved fast was a modded 99g 5speed (stillen pop, eibach springs, and 17 inch rims ) with average mileage. the owner sold it in in three days, before i had a chance to look at it. he sold it at a rock bottom 12.5.