DECLARE @t1 TABLE(CarID INT)
DECLARE @t2 TABLE(id INT,perCarID INT,scort INT)
INSERT INTO @t1
SELECT 1 UNION ALL
SELECT 2
INSERT INTO @t2
SELECT '1','1','98' UNION ALL
SELECT '2','2','50' UNION ALL
SELECT '3','2','68' UNION ALL
SELECT '4','1','70' UNION ALL
SELECT '5','2','80' UNION ALL
SELECT '6','1','92'
;WITH CTE AS
(
SELECT * FROM @t1 t1 
    CROSS APPLY 
    (
        SELECT TOP 2 scort  
        FROM @t2 
        WHERE t1.CarID=perCarID
        ORDER BY scort DESC
    ) t2
)
SELECT CarID,scort=STUFF((SELECT ','+CAST(scort AS VARCHAR) FROM CTE WHERE CarID=c.CarID FOR XML PATH('') ),1,1,'' ) 
FROM CTE c
GROUP BY c.CarID