Luton have signed former Peterborough and Brighton striker Craig Mackail-Smith on a two-year deal.
Norwich City have completed the signing of goalkeeper Jake Kean following his release from Blackburn Rovers.
QPR's owners have splashed the cash in a bid to stay among the elite yet have spent the majority of the club's return to the top-flight looking up from the bottom.
After only surviving on the final day last season QPR have won just three league games this time around and, with 10 games left, are four points adrift of safety in last place.
It would appear a poor return on lavish investment that was this week detailed by the release of the club's accounts for last season.
The figures showed player wages doubled to £56million while net debt stood at £89million - numbers that do not even reflect the influx of expensive names since the summer.
Park Ji-sung, Julio Cesar and Jose Bosingwa arrived as reinforcements but when they failed to inspire an upturn in fortunes the club twice broke their record transfer fee to sign Loic Remy and Christopher Samba in January.
Redknapp was himself brought in as a part of the continued overhaul after Mark Hughes failed to win any of the opening 13 league games.
Redknapp's presence, plus the QPR owners' heavy spending, has inevitably led to parallels being drawn to Portsmouth's decaying fortunes following their own Premier League extravagances.
Redknapp is, however, confident such a scenario will not envelop his current employers.
The 66-year-old believes QPR have acted smarter in the transfer market - bringing in players with a high re-sale value - to ensure any revenue lost from relegation could be quickly recouped.
"I only know the players I have bought since I came here and you won't have any problem (selling them)," he said.
"If the worst came to the worst you could sell Samba or Remy. They were two buys you make where there wasn't much of a downside to them.
"The club turned down more money for Samba than we paid for him from a Russian club so you'll always get your money for him and Remy is exactly the same.
"There will always be buyers for good players. Selling bad players; overpaid, bad players is the difficulty.
"That's where you can get in trouble. There is not a market for bad ones who get too much money, that is your problem."
Portsmouth were unable to sell their way out of trouble once their financial crisis hit, despite offloading almost £100million in player sales.
Redknapp had left before Portsmouth's problems took hold and, while his tenure brought the highs of an FA Cup success, he was quick to point out any subsequent financial demise should not fall on the manager.
"I don't ask the chairman to spend his money," he said.
"If he wants to bring a player in then so be it. As a football manager I can't make someone spend money."
It is a scenario Redknapp believes holds true at QPR, where he believes the owners are accountable for their spending.
"There is not going to be meltdown because of something I've done," he said.
"If the (financial) results aren't good that was before I came to the club.
"I hope (QPR don't follow Portsmouth's fall), but I don't know the situation of the owners any more than I knew the situation of the owners at Portsmouth.
"He was a young Russian guy who was a friend of Roman Abramovich. When they buy the football club you don't know whether he is richer than Abramovich, so when they want to spend money on the team, what do you do?
"You don't say, 'I'm sorry you can't spend that money because I don't know if you've got it or not'.
"It's their decision."
When Redknapp took over the QPR hot-seat in late November they had just four points and at the time he decreed it his "toughest challenge".
Redknapp's first game in charge was at Sunderland, who visit Loftus Road on Saturday , and almost four months on he sees things no differently - adding only that saving QPR would be a greater achievement than when he helped rescue Portsmouth in 2005/06.
"For sure, from where we started here, it would be," he said.
"It's just a long way to go and we really are taking it week to week.
"Tomorrow's just another big game. If we can make it back-to-back wins, it would make such a difference.
"There would be nothing more that I would like to keep the club up because the people here are lovely.
"I would like to do it for them. They are proper nice people. I can't say it enough times. I mean it."