Awesome ...werent you using solid audio f2500d on 3500 pioneer ?
Prs d2000spl is yo (H)option sir ... It's the Competion line up of pioneer ..
What Are your power requirements ...rms? For future upgrades ..mono amplifier is a very important ..decide test and weight all options before you buy anything (this was said to me)
Rockford fosgate t1500bd is available new at haroon radio Karachi for 58k
Rf are beast amps ..for SPL oriented setups these are best ... Avoid clipping with pureest power to subs .
It all depends what you need to power bro for pioneer 3500 woofer both will surve ,as it's a 1000wrms sub
Enclosure is also important in SPL setups ... Sub does what box tells it to(quote of a late SPL head )
Likewise electricals need to be upgraded also ..