Linked Server Slow Query Return

Hello can some one explain this to me and give me some advice. I have sqlserver1 and sqlserver2 I have a linked server set up [ipaddress] on both servers. When I pass a variable to the stored proc or the query it takes up to 20 seconds to return 1 row but if I replace my varibles like email='sqlboy@coxnet' and firstname='ted' and lastname='clien' it returns the one row im looking for in about 2 seconds but if I pass email =@email ,fname=@fname,lname=@lname I get the 20 second thing. The query is a stored proc being called from an asp app. I get the same results when I run this in query analyzer.

Here is the query.

DECLARE @email VARCHAR(75),@fname VARCHAR(50),@lname VARCHAR(100)

IF EXISTS (SELECT TOP 1 email
FROM [ipaddress].{database}.dbo.{tablename}--server1
WHERE email = @email )
BEGIN
set nocount on
SELECT TOP 1 email,
FIRSTNAME,
MIDDLENAME,
LASTNAME,
TITLE,
COMPANYNAME,
ADDRESS1,
ADDRESS2,
CITY,
STATE,
ZIP,
COUNTRY
FROM [ipaddress].{database}.dbo.{tablename} --server2
WHERE email in(SELECT EMAIL
FROM [ipaddress].{database}.dbo.{tablename} where email=@email--server1)
AND RecordStatusID ='1' and FirstName=@fname and LastName=@lname
END
ELSE

IF EXISTS (SELECT top 1 email,
FIRSTNAME,
MIDDLEINITIAL,
LASTNAME,
TITLE,
COMPANYNAME,
ADDRESS1,
ADDRESS2,
CITY,
STATE,
ZIP,
COUNTRY
FROM {databases}.dbo.attendees--server1
WHERE email =@email and FirstName=@fname and LastName=@lname)
BEGIN
SELECT TOP 1 email,
firstname,
MIDDLEINITIAL AS MIDDLENAME,
lastname,
title,
companyname,
address1,
address2,
city,
state,
zip,
country
FROM {database}.dbo.attendees --server1
WHERE email in (SELECT DISTINCT email
FROM server1.dbo.ebooksrequests--server1
where email=@email) and email=@email and FirstName=@fname and LastName=@lname
SET NOCOUNT OFF

END