diff --git a/Controllers/APIController.cs b/Controllers/APIController.cs
index 068e787..a5fd82d 100644
--- a/Controllers/APIController.cs
+++ b/Controllers/APIController.cs
@@ -120,7 +120,14 @@ namespace CarCareTracker.Controllers
             {
                 result = _userLogic.FilterUserVehicles(result, GetUserID());
             }
-            return Json(result);
+            if (_config.GetInvariantApi() || Request.Headers.ContainsKey("culture-invariant"))
+            {
+                return Json(result, StaticHelper.GetInvariantOption());
+            }
+            else
+            {
+                return Json(result);
+            }
         }
 
         [HttpGet]
diff --git a/Models/Vehicle.cs b/Models/Vehicle.cs
index 6b45d21..6957b79 100644
--- a/Models/Vehicle.cs
+++ b/Models/Vehicle.cs
@@ -1,4 +1,6 @@
-namespace CarCareTracker.Models
+using System.Text.Json.Serialization;
+
+namespace CarCareTracker.Models
 {
     public class Vehicle
     {
@@ -8,7 +10,9 @@
         public string Make { get; set; }
         public string Model { get; set; }
         public string LicensePlate { get; set; }
+        [JsonConverter(typeof(FromDateOptional))]
         public string PurchaseDate { get; set; }
+        [JsonConverter(typeof(FromDateOptional))]
         public string SoldDate { get; set; }
         public decimal PurchasePrice { get; set; }
         public decimal SoldPrice { get; set; }
@@ -22,10 +26,12 @@
         /// <summary>
         /// Primarily used for vehicles with odometer units different from user's settings.
         /// </summary>
+        [JsonConverter(typeof(FromDecimalOptional))]
         public string OdometerMultiplier { get; set; } = "1";
         /// <summary>
         /// Primarily used for vehicles where the odometer does not reflect actual mileage.
         /// </summary>
+        [JsonConverter(typeof(FromIntOptional))]
         public string OdometerDifference { get; set; } = "0";
         public List<DashboardMetric> DashboardMetrics { get; set; } = new List<DashboardMetric>();
         /// <summary>
diff --git a/Views/Vehicle/_VehicleModal.cshtml b/Views/Vehicle/_VehicleModal.cshtml
index 955b5a7..cdb3201 100644
--- a/Views/Vehicle/_VehicleModal.cshtml
+++ b/Views/Vehicle/_VehicleModal.cshtml
@@ -89,9 +89,15 @@
                             </div>
                             <div id="collapsePurchaseInfo" class="accordion-collapse collapse" data-bs-parent="#vehicleModalAccordion">
                                 <label for="inputPurchaseDate">@translator.Translate(userLanguage, "Purchased Date(optional)")</label>
-                                <input type="text" id="inputPurchaseDate" class="form-control" placeholder="@translator.Translate(userLanguage, "Purchased Date")" value="@Model.PurchaseDate">
+                                <div class="input-group">
+                                    <input type="text" id="inputPurchaseDate" class="form-control" placeholder="@translator.Translate(userLanguage, "Purchased Date")" value="@Model.PurchaseDate">
+                                    <span class="input-group-text"><i class="bi bi-calendar-event"></i></span>
+                                </div>
                                 <label for="inputSoldDate">@translator.Translate(userLanguage, "Sold Date(optional)")</label>
-                                <input type="text" id="inputSoldDate" class="form-control" placeholder="@translator.Translate(userLanguage, "Sold Date")" value="@Model.SoldDate">
+                                <div class="input-group">
+                                    <input type="text" id="inputSoldDate" class="form-control" placeholder="@translator.Translate(userLanguage, "Sold Date")" value="@Model.SoldDate">
+                                    <span class="input-group-text"><i class="bi bi-calendar-event"></i></span>
+                                </div>
                                 <label for="inputPurchasePrice">@translator.Translate(userLanguage, "Purchased Price(optional)")</label>
                                 <input type="text" inputmode="decimal" onkeydown="interceptDecimalKeys(event)" onkeyup="fixDecimalInput(this, 2)" id="inputPurchasePrice" class="form-control" placeholder="@translator.Translate(userLanguage, "Purchased Price")" value="@(Model.PurchasePrice == default ? "" : Model.PurchasePrice)">
                                 <label for="inputSoldPrice">@translator.Translate(userLanguage, "Sold Price(optional)")</label>