diff --git a/scrapling/spiders/request.py b/scrapling/spiders/request.py
index ce728ee2..ef766b2c 100644
--- a/scrapling/spiders/request.py
+++ b/scrapling/spiders/request.py
@@ -22,6 +22,13 @@ def _convert_to_bytes(value: str | bytes) -> bytes:
     return value.encode(encoding="utf-8", errors="ignore")
 
 
+def _stable_value_repr(value: Any) -> str:
+    try:
+        return orjson.dumps(value, option=orjson.OPT_SORT_KEYS, default=repr).decode()
+    except TypeError:
+        return repr(value)
+
+
 class Request:
     def __init__(
         self,
@@ -97,15 +104,19 @@ def update_fingerprint(
         }
 
         if include_kwargs:
-            kwargs = (key.lower() for key in self._session_kwargs.keys() if key.lower() not in ("data", "json"))
-            data["kwargs"] = "".join(set(_convert_to_bytes(key).hex() for key in kwargs))
+            filtered_kwargs = {
+                key.lower(): _stable_value_repr(value)
+                for key, value in self._session_kwargs.items()
+                if key.lower() not in ("data", "json")
+            }
+            data["kwargs"] = tuple(sorted(filtered_kwargs.items()))
 
         if include_headers:
             headers = self._session_kwargs.get("headers") or self._session_kwargs.get("extra_headers") or {}
             processed_headers = {}
             # Some header normalization
             for key, value in headers.items():
-                processed_headers[_convert_to_bytes(key.lower()).hex()] = _convert_to_bytes(value.lower()).hex()
+                processed_headers[_convert_to_bytes(key.lower()).hex()] = _convert_to_bytes(value).hex()
             data["headers"] = tuple(processed_headers.items())
 
         fp = hashlib.sha1(orjson.dumps(data, option=orjson.OPT_SORT_KEYS), usedforsecurity=False).digest()
diff --git a/tests/spiders/test_request.py b/tests/spiders/test_request.py
index 997a71ba..00f6c49c 100644
--- a/tests/spiders/test_request.py
+++ b/tests/spiders/test_request.py
@@ -99,6 +99,38 @@ def test_fingerprint_different_urls(self):
         r2 = Request("https://example.com/page2")
         assert r1.update_fingerprint() != r2.update_fingerprint()
 
+    def test_fingerprint_include_kwargs_uses_kwarg_values(self):
+        """Test kwargs with different values produce different fingerprints."""
+        r1 = Request("https://example.com", timeout=1)
+        r2 = Request("https://example.com", timeout=2)
+
+        assert r1.update_fingerprint(include_kwargs=True) != r2.update_fingerprint(include_kwargs=True)
+
+    def test_fingerprint_include_kwargs_handles_non_primitive_values(self):
+        class _Opaque:
+            def __repr__(self) -> str:
+                return "_Opaque(stable)"
+
+        opaque = _Opaque()
+        r1 = Request("https://example.com", proxies={"http": "p1"}, custom=opaque)
+        r2 = Request("https://example.com", proxies={"http": "p1"}, custom=opaque)
+        r3 = Request("https://example.com", proxies={"http": "p2"}, custom=opaque)
+
+        fp1 = r1.update_fingerprint(include_kwargs=True)
+        r2._fp = None
+        fp2 = r2.update_fingerprint(include_kwargs=True)
+        fp3 = r3.update_fingerprint(include_kwargs=True)
+
+        assert fp1 == fp2
+        assert fp1 != fp3
+
+    def test_fingerprint_include_headers_preserves_header_value_case(self):
+        """Test header values are fingerprinted without lowercasing."""
+        r1 = Request("https://example.com", headers={"X-Test": "A"})
+        r2 = Request("https://example.com", headers={"X-Test": "a"})
+
+        assert r1.update_fingerprint(include_headers=True) != r2.update_fingerprint(include_headers=True)
+
 
 class TestRequestCopy:
     """Test Request copy functionality."""