Thinking of getting 2 Kenwood - 10" 4-Ohm Single-Voice-Coil Subwoofers what power amp should i get?

Is the amp a single channel? If so, the only way to connect the subs (without overloading the 2 ohm stable amp) is to wire each sub's voice coils in parallel (2 ohm) and then connecting the subs in series (4 ohms). If the amp is two channel, the subs can have their voice coils connected in parallel (as before) and then each sub connected to its own channel.

Simple power fom amo to power on sub. Ground on amp to ground on sub

Ok, your post has two different models listed. Let's start with something you need to know about your amplifier. Is it one ohm or two ohm stable. This will make a difference. Also, whether your subs are single voicecoil (HFI12s4) or dual voice coil (HDI12d4).

Let's start with the easy scenario. Let's say your amp is two ohm stable and you have two single voice coil subs. It's simple. You go from the positive of the amp to the positive of both subs and the negative of the amp to the negative of both subs. This will provide a 2 ohm load to the amplifier, thus pulling all the power out of it.

Unfortunatley, if you have two dual voice coil subs, you won't be as efficient. You will only have the options of a 4 ohm load or a 1 ohm load.

This is where having a one ohm stable amp would come in handy. If the amp is one ohm stable, hook the positive of the amp to all 4 of the positives on the subs, and hook the negative of the amp to all 4 negatives of the subs. This produces a 1 ohm load.

WARNING!! If you have a 2 ohm stable amp DO NOT use the last wiring scenario. It will fry your amp.

Now, the last is a little trickier. This is for two dual 4 ohm subs. Follow closely. Hook the positive of the amp to one of the positives of each sub. (do the next step to both subs) Go from the negative of the voice coil that you hooked positive from the amp is hooked to, and hook that to the positive of the unused voice coil. Then go from the negative of that voice coil and hook to the negative of the amp. Make sure this is done on both subs. This will give you a 4 ohm load.

Hope this helps

Is your sub single or dual voice coil. This will also make a difference in choosing amps. Pretty much any amp that will supply your required power will do. But, if you have a single voice coil sub, you will be wanting to look for RMS power at 4 ohms. If you have a dual 4 ohm voice coil sub, you can wire it to a 2 ohm load. Then you will need to search for amps that supply the RMS requirements of the sub at 2 ohms. The choices are almost endless. I am an RE Audio dealer, so I absolutely know that they will do you well. Hope this helps.

In order to get the bass you want, you'll run your amp switched as a two channel amp and you'll need to run your subwoofers in 4 ohm Mono that's 450 x 2 to give you 900 watts of power.

2, 2 ohm dual voice coils ran in series and bridged on the amp for each sub.

Otherwise, Single Voice Coil 4 ohm subwoofers bridged to amp.

off the same amp? you have two way different sounding speakers man. you can buy 2 identical speakers from the same company and brand and series and they will play differently every time. you have 2 speakers with nothing in common so you will hear a difference and maybe interference because of the different ohm levels.

Yes, you sure could. Each sub is a 4 ohm load. When you put them in a box connect a wire from the + terminal on each speaker, and connect that to the + terminal on the box. Do the same from each - terminal, connecting to the - terminal on the box.
This is called "wiring in parallel" and it will split the load in half, so you present a 2 ohm load to the amp. Since your amp is rated down to 1 ohm, it will work just great.

THE T9510-04 SUBS ARE SINGLE COIL SUBS AND YOU CAN VIEW THAT WIRING DIAGRAM AT THE FOLLOWING LINK:
http://www.mtx.com/caraudio/products/subwoofers/TechData_T9510-04.pdf

THE T9510-44 SUBS ARE DUAL VOICE-COIL SUBS AND YOU CAN VIEW THAT WIRING DIAGRAM AT THE FOLLOWING LINK:
http://www.mtx.com/caraudio/products/subwoofers/TechData_T9510-44.pdf

SINCE YOU NEED A 1 OHM LOAD, I PRESUME BRIDGED AND ARE USING TWO SUBS, THEN HOPEFULLY YOU HAVE THE DUAL VOICE COIL TYPE, AS THEY ARE DUAL 4 OHM AND YOU WILL HAVE TO CONNECT THE VOICE-COILS IN PARALLEL WHICH WILL MAKE EACH SPEAKER A 2 OHM SPEAKER AND THEN CONNECT THE TWO SPEAKERS THEMSELVES IN PARALLEL AND THIS WILL PROVIDE YOU THE 1 OHM LOAD. IF YOU IN FACT HAVE THE SINGLE 4 OHM VOICE COIL VERSION, THEN IT WILL ONLY PARALLEL THE PAIR DOWN TO 2 OHMS. OK. LET ME KNOW IF YOU NEED FURTHER ASSISTANCE.....V

You can't run parrallel on 3 single voice coil subwoofers. If you run all the negatives from each coil and possitives from each coil to one terminal you will be dividing the ohms by 3. I don't think JL ever made a single voice coil 2 ohm subwoofer though. If you ran a parrallel on 3 8 ohms you would be at 2.7 ohms. 3 4 ohm would put you down to 1.3