need a GPS OEM receiver using GP2015+GP2021(or GP4020) chipset

Hi, guys,

I am now planing to modify a commercial receiver to develop a GPS IF 
data collecting system and so looking for a GPS OEM receiver which 
emploies GP2015+GP2021 chipset.
For the receiver, what I need to know is which pin outputs GPS IF signal 
and what are the IF data frequency and the base-band frequency of GPS 
signal?
Is there any one can tell me if the Garmin GP25 series receiver uses the 
GP2015 chip?  Or, could any one suggest me a GPS product which can meet 
my requirement?
Thanks a lot.

Best Regards

Moncton