What model TiVo are you looking to upgrade?

Philips Standalone (without built-in DirecTV)	Philips DirecTV/Tivo (with built-in DirecTV)
PTV100 PTV300 HDR110 HDR112 HDR212 HDR312 HDR31201 HDR31202 HDR31203 HDR31204 HDR612	DSR6000 DSR6000R DSR6000R01 DSR7000 DSR704 DSR708
Sony	Hughes TiVo
SVR-2000 SVR-3000 SAT T-60	GXCEBOT GXCEBOTD HR10-250 HDVR2 SD-DVR40 SD-DVR80 SD-DVR120
AT&T and TiVo-branded	Other Models
TCD130040 TCD140060 TCD540040 TCD540080 TCD540140 TCD649080 TCD649180 TCD746320 TCD746500 TCD750500 TCD748000 TCD758250 TCD230040 TCD240040 TCD24004A TCD240080 TCD24008A TCD240140 TCD648250 TCD648250b TCD652160 TCD658000   TCD846500 TCD848000 TCD840300 TiVo Bolt (all models)	RCA DVR39 RCA DVR40 RCA DVR80 Samsung SIR-S4120R Samsung SIR-S4080R Samsung SIR-S4040R Pioneer 810H Pioneer 57H Humax T800 Humax T2500 Humax DRT400 Humax DRT800 Toshiba SD-H400 Toshiba RS-TX20 Toshiba RS-TX60
DirecTV Branded
R10 HR10-250 THR22 HR2X (HR20, HR21, HR22, HR23, HR24) HR34, HR44, HR54(Genie)
I'm not sure...