docs: update documentation for normalized config and improve command

- Add improve command to all command tables and usage sections
- Add normalized_config field to BestCarRecord struct documentation
- Update CarCounts.by_rid type from String to (String, String)
- Update CarCounts.guid_to_rid type to HashMap<String, HashSet<(String, String)>>
- Add owned_configs field to MyCarsData and CarCounts docs
- Add normalize_to_final_build() to API docs
- Update CSV format examples to include FinalBuild column
- Update my_cars.json structure with engineMajor/weightMajor/chassisMajor
- Update timing file example with v2c_ version prefix
- Add version prefix stripping to data transformation docs
- Update CHANGELOG.md with Unreleased section
- Fix compare_records description to include normalized config sorting

docs/USER_GUIDE.md

@@ -86,18 +86,18 @@ cargo run --bin records -- best --min-count 5
 
 `best.csv`:
 ```csv
-RQ,Brand,Model,Year,Count
-85,McLaren,F1,1993,15
-82,Ferrari,250 GTO,1962,12
-80,Lamborghini,Countach,1974,8
-75,Porsche,911 Turbo,1975,6
+RQ,Brand,Model,Year,FinalBuild,Count
+85,McLaren,F1,1993,323,15
+82,Ferrari,250 GTO,1962,332,12
+80,Lamborghini,Countach,1974,233,8
+75,Porsche,911 Turbo,1975,332,6
 ```
 
 `very_best.csv`:
 ```csv
-RQ,Brand,Model,Year,Count
-85,McLaren,F1,1993,15
-82,Ferrari,250 GTO,1962,12
+RQ,Brand,Model,Year,FinalBuild,Count
+85,McLaren,F1,1993,323,15
+82,Ferrari,250 GTO,1962,332,12
 ```
 
 **Understanding the output:**
@@ -105,6 +105,7 @@ RQ,Brand,Model,Year,Count
 - **Brand**: Car manufacturer
 - **Model**: Car model name
 - **Year**: Model year
+- **FinalBuild**: Normalized tune configuration (323, 233, or 332)
 - **Count**: How many times this car was the fastest across different tracks
 
 **Interpretation:**
@@ -164,24 +165,24 @@ cargo run --bin records -- wishlist --min-count 5 --max-wishlist 500
 
 `wishlist.csv`:
 ```csv
-RQ,Brand,Model,Year,Count
-90,Pagani,Zonda R,2010,18
-88,Ferrari,F40,1987,15
-87,McLaren,Senna,2018,12
+RQ,Brand,Model,Year,FinalBuild,Count
+90,Pagani,Zonda R,2010,323,18
+88,Ferrari,F40,1987,332,15
+87,McLaren,Senna,2018,233,12
 ```
 
 `add.csv`:
 ```csv
-RQ,Brand,Model,Year,Count
-90,Pagani,Zonda R,2010,18
-88,Ferrari,F40,1987,15
+RQ,Brand,Model,Year,FinalBuild,Count
+90,Pagani,Zonda R,2010,323,18
+88,Ferrari,F40,1987,332,15
 ```
 
 `remove.csv`:
 ```csv
-RQ,Brand,Model,Year,Count
-75,BMW,M3,2003,3
-72,Audi,RS6,2002,2
+RQ,Brand,Model,Year,FinalBuild,Count
+75,BMW,M3,2003,332,3
+72,Audi,RS6,2002,233,2
 ```
 
 **Action items:**
@@ -196,7 +197,7 @@ RQ,Brand,Model,Year,Count
 cargo run --bin records -- all
 ```
 
-**Purpose:** Generates all 6 CSV files in a single parse pass. Equivalent to running `best`, `trash`, and `wishlist` together, but more efficient since data is only parsed once.
+**Purpose:** Generates all 7 CSV files in a single parse pass. Equivalent to running `best`, `trash`, `wishlist`, and `improve` together, but more efficient since data is only parsed once.
 
 **Flags:**
 - `--min-count N` — Minimum number of tracks for "very best" qualification (default: 10)
@@ -214,6 +215,38 @@ cargo run --bin records -- all --min-count 5 --max-wishlist 500
 - `wishlist.csv` — Ideal wishlist (very_best unowned, capped)
 - `add.csv` — Cars to add to wishlist
 - `remove.csv` — Cars to remove from wishlist
+- `improve.csv` — Owned cars not yet at final build config
+
+#### Improve Analysis
+
+**Command:**
+```bash
+cargo run --bin records -- improve
+```
+
+**Purpose:** Generates `improve.csv` — owned cars whose actual tune configuration is not yet a final build (323, 233, or 332). Sorted by number of best tracks descending, so the most impactful upgrades appear first.
+
+**Output File:**
+
+`improve.csv`:
+```csv
+RQ,Brand,Model,Year,Target,Count
+90,Pagani,Zonda R,2010,323,18
+85,McLaren,F1,1993,332,15
+```
+
+**Understanding the output:**
+- **RQ**: Car's rarity level
+- **Brand**: Car manufacturer
+- **Model**: Car model name
+- **Year**: Model year
+- **Target**: The final build config the player should upgrade to
+- **Count**: How many tracks this car is best on (across all its configs)
+
+**Interpretation:**
+- Focus on cars with the highest Count first — upgrading them benefits the most tracks
+- The Target column shows which of the three final builds (323, 233, 332) to aim for
+- Cars already at a final build or maxed config are automatically excluded
 
 #### Detailed Performance Data
 
@@ -285,19 +318,20 @@ cargo run --bin records -- fetch && cargo run --bin records -- all
 ### What `all` Does
 
 1. **Parses** all timing data in a single pass
-2. **Generates** all 6 output CSV files
-3. **Sorts** all files by car RQ
+2. **Generates** all 7 output CSV files
+3. **Sorts** all files by car RQ (and FinalBuild where applicable)
 
 ### Output Files
 
 | File | Format | Description |
 |------|--------|-------------|
-| `best.csv` | `RQ,Brand,Model,Year,Count` | All cars best on at least one track |
-| `very_best.csv` | `RQ,Brand,Model,Year,Count` | Cars best on ≥ min_count tracks |
+| `best.csv` | `RQ,Brand,Model,Year,FinalBuild,Count` | All cars best on at least one track |
+| `very_best.csv` | `RQ,Brand,Model,Year,FinalBuild,Count` | Cars best on ≥ min_count tracks |
 | `trash.csv` | `RQ,Brand,Model,Year` | Owned cars not best on any track (RQ<80, not prize) |
-| `wishlist.csv` | `RQ,Brand,Model,Year,Count` | Ideal wishlist (very_best unowned, capped) |
-| `add.csv` | `RQ,Brand,Model,Year,Count` | Cars to add to wishlist |
-| `remove.csv` | `RQ,Brand,Model,Year,Count` | Cars to remove from wishlist |
+| `wishlist.csv` | `RQ,Brand,Model,Year,FinalBuild,Count` | Ideal wishlist (very_best unowned, capped) |
+| `add.csv` | `RQ,Brand,Model,Year,FinalBuild,Count` | Cars to add to wishlist |
+| `remove.csv` | `RQ,Brand,Model,Year,FinalBuild,Count` | Cars to remove from wishlist |
+| `improve.csv` | `RQ,Brand,Model,Year,Target,Count` | Owned cars not yet at final build config |
 
 ### Typical Daily Routine
 
@@ -421,7 +455,7 @@ The tool generates CSV files for external analysis. All files are sorted by car
 
 #### "Please provide a command"
 **Problem:** No arguments provided
-**Solution:** Use `best`, `trash`, `wishlist`, `all`, `details`, `track`, or `fetch`
+**Solution:** Use `best`, `trash`, `wishlist`, `all`, `details`, `track`, `improve`, or `fetch`
 
 #### "Could not read my cars file" / "Missing data file"
 **Problem:** `my_cars.json` (or another data file) not found or not readable